OIl pressure still drops after changing oil sending unit?

Asked by Feb 06, 2013 at 10:06 PM about the 2009 Chevrolet Silverado 1500 LTZ Crew Cab 4WD

Question type: Maintenance & Repair

When truck is first started, oil pressure is normal, around 40 psi. When engine temp starts up, oil pressure slowly falls until "Stop Engine - Low Oil Pressure" warning comes on. Switch truck off a few second, maybe 20-30, restart truck and back to 40. And on and on. I've never seen a bad oil filter but is that possible. Filter has about 2000 miles on it and not had problems until now??? 5.3L

93 Answers

100,675

Did you check the pressure with a mechanical gauge? Does the engine make noise when there is a low pressure indicated? --- If there is pressure in the engine and going on the assumption that the indication is bad, check the ohms of the sending unit - it should remain steady. Check the voltage to the gauge it should be a steady 12-13.5 volts. --- A oil pressure gauge in actually a voltage gauge with a different face. 12 volts on the supply side and the sending unit actually varies the resistance to ground.

23 of 23 people found this helpful.
2,180

i have seen a bunch of these truks with this problem and what it iis there is a small screen under the oil pressure switch that gets sludge in it and stops oil from reaching your pressure sensor, remove your oil pressure sensor on rear of intake and take a small pick and pull out the screen and throw it away, reinstall our oil pressure sensor.

126 of 126 people found this helpful.

I have this exact problem. It is obviously oiling because there is no difference in the sound of the motor from before the problem to now. Purrs like a kitten even though the dash lights are going crazy and the guage drops to zero in about a minuet. So..My 2009 5.3L just started this crap. New sensor is $80 bucks...Question to last poster...so is it safe to remove the screen a reuse the sensor? How many times have you done this? Isnt that like putting a bad part back on after going through the pain of fixing it. It is a special order part at O'Rileys...

32 of 32 people found this helpful.
2,180

You can install new sensor while you have it out but if sensor is not leaking oil I would clean out pressure hole in end of sensor, throw that stupid screen away and go with it and removing screen won't hurt anything, all it does it collect sludge an plug up, the never had them before !

31 of 31 people found this helpful.
820

I have a similar (maybe different) problem... I have an 2003 avalanche 5.3 180K miles was on a road trip. leaving for home as I started "low oil pressure" warning came on for about 30 seconds as I was driving-then went off...went to first gas station..checked oil..level was fine. Drove 4 hours home..warning chime went off one other time for about 10 seconds..then off again. took it to a shop next day, when driving there, no warning messages.. He said motor is shot..suggested a reman replacement $4500. told him I needed to think about it I was gonna come pick it up. Went to pick it up. "low oil pressure"warning came on as soon as I started it, it ran 10 seconds and shut down. so I have 1 time a warning shortly after start, then another after it ran at highway speeds (power felt fine) for 4 hours..and now I got the warning at start up.. Any ideas? suggestions? I am the original owner and have maintained the truck pretty well...is the motor really shot at 180K ?

82 of 82 people found this helpful.
200

Change the oil pressure sensor (aka oil pressure sending unit). Also, if it happens to have a filter below the sensor, replace/clean that also. You'll need a 27mm deep socket, a 1/2 to 3/8 adapter, and 1 or 2 extensions. It's behind the intake manifold, near the firewall. Kind of a pain to get to. I personally filed away some of the plastic casting from the intake manifold, on the driver side to make more room... otherwise, expect a bloody knuckle (the one below your thumb). Worked great. Enjoy.

20 of 20 people found this helpful.
310

I changed the filter under the oil sending unit. I suggest carefully removing the alternator and then the intake manafold. Get a new gasket set and this will make your engine run better too with 100k miles on it. This can be done start to finish in 2 hours. It will fix your problem. If the motor does not start rattling immediately when the Guage drops it's still oiling. Just a stopped up badly designed GM sensor. CA

12 of 12 people found this helpful.
310

BTW you will need a screw or a pick to stick down in the oil sending unit hole after it is removed and pick that 2 inch long filter out of the hole. It IS NOT attached to the sending unit. You will have to coax it out.

14 of 14 people found this helpful.
10

I had the same issue but with my Oldsmobile 88. I changed the pressure sensor. What should I expect next or by changing the pressure sensor fixed my issue, because I was on a date and Bamm all the oil dropped. Next day I changed it like mentioned before and now the oil is still there. My question is. Should I expect another issue or not? Thanks in advance.

1 of 1 people found this helpful.
160

If your hydraulic lifters are in good shape you will not hear the classic no oil lifter tap until after about 15 to 20 seconds or more of no oil. Once you start hearing the tap you are doing damage to the lifters (not to mention the rest or the motor) If you do not have the ability to determine beyond a doubt that oil is really flowing take it to someone who can or you are going to toast your motor.

7 of 7 people found this helpful.
410

I have had the same issue with my 08 Chevy but NOTHING has fixed it! We replaced the OPSU 3 times. The filter wasn't even in place when the unit was changed. Check engine light still came back on. So my whole engine was taken apart and cleaned, filters changed, oil pump changed and anything and everything that could be done has been done. After the full cleaning the light went off for long enough for me to pass emissions and had stayed off for 3 months... And you guessed it... Check engine light is back on. Any suggestions??

41 of 41 people found this helpful.
330

Forget replacing the sensor. Here is the deal. There is a filter that sits just below the sensor in the intake manifold that gets clogged preventing the sensor from reading the pressure. I just bought one for $12.00 from the dealer. My dealer wants $300.00 to replace the sensor and filter. Not sure I want to make a mess of my hands!

17 of 17 people found this helpful.
370

Is that filter in every engine? I've got a 2004 Sierra with the 5.3. New mains, new rod bearings, new rings, new oil pump, new lifters, reman heads. Oil pressure fluctuates from 20-45 with no rhyme or reason. Doesn't matter whether or not the engine rpm's are up or at idle.

33 of 33 people found this helpful.
330

Certainly sounds like the oil pressure sensor filter. That is how it started for me. Then got progressively worse as the filter became more clogged. I would go to the parts department at a dealer and let them get a blowup of your engine intake manifold and will be surprised if it is not there. Should be in the back of the manifold.

7 of 7 people found this helpful.
170

2001 tahoe reading highoil pressure changed oil and sending unit still the same.. guage wount drop back down after shutting engine off

17 of 17 people found this helpful.
70

I hate to be the bearer of bad news but your crankshaft bearings are shot I have the same problem with my 2003 Tahoe this is due to inferior metals that they put in the Bering crankshaft low bid I guess. Oh by the way I bought new in 2003 have only 137K and used synthetics only every 5K. I hate GM

7 of 7 people found this helpful.
330

Don't know about early models BUT it is the FILTER under the oil pressure sending unit getting clogged. Had it replaced 3 times by the dealer under warranty. They even confirmed that is what was. Mine is a 6.0 2007 new body style Silverado. Change your oil allot.

9 of 9 people found this helpful.
260

I have an 09 GMC Sierra with a 5.3 liter. I've recently had oil consumption problems took it to the dealer they ended up putting new piston and rings new lifters and since I've got it back it tIcks really bad on dry start. Once oil pressure builds up it goes away, but it seem that it takes the pressure a little longer to build than usual. Warranty just ran out.. any suggestions?

26 of 26 people found this helpful.
170

I have been having this identical problem, however the pressure only drops when I weight in the back or I am towing heavy....outside of that, oil pressure always stays on target. still the filer / screen?

17 of 17 people found this helpful.
160

I just had the same problem of no oil pressure. '09 5.3 ltr. Took to local guy, he suspected the screen right away. New sending unit, cleaned the plugged screen, oil change, and $250 fixed the problem. Truck has 110,000 miles, and it sounds like all are going to do this. Good luck.

16 of 16 people found this helpful.
130

I have a 2008 GMC Sierra Denali with the 6.2l... I have had similar issues where rather suddenly I would be running at about 22-25psi oil pressure at 70mph... At first I thought there was an issue with the oil, as, after a full oil change including filter would put everything back to normal... Well, this time it happened with only 4k miles on the oil... Decided to only change the spin on oil filter... Well, as figures, oil pressure went right back to normal. These tiny spin-on oil filters appear to be really cr*ppy!!! Waging a guess, they are collapsing over time... Definitely recommend trying a quick-filter only swap to see if any of these pressure problems we see are related to these sin-on filters. I've tried various brands (NEVER Fram), but have typically had the best luck with ACDelco filters in lasting the longest... This time not so, but thinking about installing a remote-oil filter kit with a MUCH bigger filter... I typically run 8.5k to 10k miles, always mobile 1 synthetic... I even have had my oil analyzed by Blackstone labs at 10k... Oil looked beyond perfect, it passed with new spec... Virtually no contaminants at all... And that was at 187k on the engine...

13 of 13 people found this helpful.
120

had same problem 2007 chevy surburban. no oil pressure. changed sensor no change. checked input voltage and gauge circuit all ok. changed oil filter(some one put on no name one) fixed problem.( I always use mobil 1 filters) great oil pressure now. hope this will help someone else

12 of 12 people found this helpful.
300

the problems you are experiencing could be related to the o ring on the siphon tube going to the oil pump. An $8 part can cause you a lot of headache as I have found out twice now.

12 of 12 people found this helpful.
290

I have a 2007 Suburban with LC9 engine 8th digit #3. Uses oil like crazy, 165,000 stuck AFM lifter.I replaced that one lifter (yes just that one $$) and everything is fine, 180,000 still using oil like crazy, Starting to blue/white smoke on start up. Low oil pressure alarm comes on then goes to 'Shut off engine alarm" then goes away... back and forth while driving. I flush engine and change engine oil and install new Bosch oil filter then I changed out the oil pressure switch and looked at the screen underneath the sensor and it didn't look bad but cleaned it anyway. Dumped 1/2 quart of accumulated oil out the intake manifold UGH, another issue !!! Started truck and instantly I have 60 pounds of pressure. And it didnt smoke on start up (remember the oil in manifold) Purr's like a kitten.Take it for a test drive and after 15 minutes pressure begins to slowly drop until same alarms come on. Next I changed the oil pump and pick-up tube o-ring and everything looks good, purr's like a kitten until I drive it and still does the same thing no oil pressure shut off engine. I was really hoping to get more miles out of this before engine replacement. And if I do should I replace with equal or upgrade to different engine. What do i do next? Cam and lifters? New engine? Any help would be appreciated, Thanks in advance !!

29 of 29 people found this helpful.
230

I have a 2007 tahoe ltz 5.3. Saturday cel came on said oil senior high pressure. Stared it up oil pressure was at 80 let it idle went to 0 pressure. Drove it 1 mile checked oi and llooked it over then drove home 25 miles gages never moved from 0 pressure. No ticking no sound from motor at all. So today had oil changed new filter still 0 pressure. Checked the code voltage high and low on abs , oil sensor and water sensor cleared them. Right back on. Reset battery started it up oil pressure went to 80 for 30 seconds then back to 0 psi. And ideas that you all for your time.

23 of 23 people found this helpful.
300

These engines have oil pressure problems for sure (aka) small block GM motors. But don't remove the small oil filter under the oil sending unit. It does serve a purpose. On engines that use lifters to cut out half the cylinders during light driving cycles this filter is used to keep small particles out of the passages. If you remove it then your spredding these particles through the lifters and solenoids that control them. There is another problem with these motors that I have repair with great sucess. Email me Mr2tyt1@gmail.com I can help

23 of 23 people found this helpful.
90

I had a similar problem with oil pressure being low. I had the Chevy dealership, replace oil sensor and screen. Two months later same problem. Decide to change oil myself. Found that the dealership used acdelco filter. Got a bosch filter at O'Reily s for $8.00. Oil pressure around 40 driving, and 30+ at idle. Seems to have fixed problem.

9 of 9 people found this helpful.
10

No pressure turn off engine on my 2007 tahoe 5.3 l v8, was overdue for oil change, went an bought ac delco oil filter changed it and knock on wood, I got oil pressure again! Hope that was it!!!

1 of 1 people found this helpful.
60

This has been a recurring problem with my 2007 Suburban 5.3L. The first time it happened, I changed my oil filter and did not see the problem for 1700 miles, then it was back. So I changed the oil and filter and it seemed that the problem was solved. I cut open the old filter and it was covered with a black substance - seemed like maybe a carbon buildup. I think this is what happens, not filters collapsing. I'm guessing it's related to the AFM. Anyway, changing oil every 5000 miles or so, no oil pressure issues for 20,000 miles. Now it seems to be back. Happened about 1000 miles ago, had the oil and filter changed and back to normal. Now after 1000 miles it happened again. I changed the filter tonight and it improved, but the pressure isn't as high as it should be. I'm going to try the sensor screen next.

6 of 6 people found this helpful.
300

I would drop the oil pan and replace the o ring on the oil pump siphon tube. I've had a couple a few like this .

5 of 5 people found this helpful.
120

I sort of have the same problem but different... I have a 1999 GMC 5.3. With 250 k miles. Give or take 10 miles... I don't know exactly since the odometer only come on occasionally.. My daughter ( the offspring) was driving it today and it just died. I went to pick it up and it had low oil pressure and sort of knocks (not a tap). It starts and has power but rattles knocks . No water in the oil and vise versa... I was told about the oil screen problem but was not sure if the truck has the right symptoms .. I use the truck to haul steel and really don't want to get rid of it but I don't want to throw money away..:. And yes I know I got my monies worth out of the old girl but I still feel like we can work things out... Love Always Willie

12 of 12 people found this helpful.
45

Ok let me throw a twist on this. Oil pressure gauge never moves off 35 - 40psi but the alarm comes on saying low oil pressure shut engine down now..... Turn the blinker on and the alarm goes away until next time. This happen when coming to a stop or during heavy drive times.

4 of 4 people found this helpful.
305

I fix this issue almost once a month now on countless ls based gm motors, i will try to give symptoms as best i can so anyone can try to tell if this is the issue you are having and i will let you know how to fix the problem. 9 out of 10 vehicles i fix with this issue will not show signs of failure but all have same problems and symptoms and if go unresolved will ultimately cost you an engine. SYMPTOMS: first start oil pressure is normal and slowly drops until shut down warning. sometimes will run a long while without dropping , ive seen some that only drop once vehicle is ran at full throttle. Problem: the oil pump in these engines have a pressure relief valve that dumps oil back into pan, in most cases the valve sticks open and is bleeding off oil pressure into the pan, and a lot of times the engine still runs nice and quiet mainly cause its got plenty of oil volume to flow through the engine just no pressure. TO Fix: Replace OIL PUMP, the pressure relief valve is made into the pump and is not changeable. I hope this may help somebody out there, good luck have any questions feel free to send me a email dsmizzledks@gmail.com

20 of 20 people found this helpful.
250

I appreciate all of the info here. Not sure "yet" if one of these will help my case. I have a 2005 Yukon XL 1500, 203K miles. Been a good vehicle. My oil pressure sensor came on for about the last 3 months... started out "monthly", oil was full. Oil is changed regularly. Now it is coming on just about every time I drive. It will start out at about 37lbs in the city driving, going down to about 10lbs or lower at red lights. On interstates, it will go up to about 57lbs. I did have a tap start shortly before this situation started. It doesn't always tap. Replaced the Oil Pressure Sensor. Did not unplug the battery afterwards cause wasn't sure if it needed to be on pre-2007 models. Don't think my husband messed with the filter that is under the oil sending unit, if it has one? If anyone has dealt with a similar year and their problem was fixed, I would appreciate your input. I have been driving it on long trips out of state, so far it has gotten me where I am going.... Thanks!

7 of 7 people found this helpful.
250

One more thing, today, I stopped the Yukon and got out to unload something, and it shut off because of the low oil pressure. It acted like it was running ragged when I got out, but because it was about to shut off. It did crank right up again.

3 of 3 people found this helpful.
30

We changed the oil pressure sensor and the filter under it and it's still doing it. So is the o ring good to start with?

3 of 3 people found this helpful.
300

That is where I would start next.

2 of 2 people found this helpful.
300

Whomeveer says the little screen filter under the oil sender dosent do anything has no idea what they are telling you. It is a vital part of the oil system especially since the change to the engine in 2007. Not a smart plan to remove it.

4 of 4 people found this helpful.
250

Here is where my 2005 Yukon XL stands today. We have changed the oil pressure sensor and cleaned the throttle body. At first I thought we had success with the throttle body cleaning as we did this about 4 months after replacing the sensor. The oil pressure is still dropping down to 5 lbs or less when I first drive and stop at a few lights. It has shut off once or twice. After warming it up, say getting on the interstate for 15 minutes or so, I generally don't have the drop after that. Hubby has now decided to replace the throttle body. Any thoughts on the O ring that is talked about here... where is it located? Thanks.

2 of 2 people found this helpful.
300

There is an issue with the camshaft thrust plate seal failing. Pressure is usally good until warm then pressure drops at idle. The seal built in the back of the plate flattens out allowing oil to bleed by.

3 of 3 people found this helpful.
300

The o ring is on the siphon tube of the oil pump pick up. You will have to drop the oil pan, take out a few other bolts, and wham you're there. O ring is about 8 bucks and is a common problem with these engines. Oil pan gasket is about 40. Do not try to reuse the old gasket as it WILL leak.

6 of 6 people found this helpful.
60

I work for a chevy dealer in parts Dept. I have the same problem. In the morning low pressure light come on and pressure to 0 but later after 10 min running it stays at 38 t0 40..The recommend me to flush the engine to clean the gums .use 5/20 in the winter. From 2007 an up they use filter at the sending unit.

6 of 6 people found this helpful.
300

I would only use oil that is recommended for these engines especially with active fuel management. The lifters in them are not cheap and getting to them are another issue. Use a good oil and these engines will last. I've got one with over 300 thousand on it using Mobile one. The only time I had issues is when I let a friend borrow it and they put the Walmart oil in it. They brought it to me with low oil pressure and I went to people I know and trust and found that these motors are infamous for the o ring on the siphon tube going bad and not sealing up.

4 of 4 people found this helpful.
300

Then the same thing happened to my 08 with AFM. Changed out o ring in both cases and both run fine to this day.

1 of 1 people found this helpful.
370

I've found that my problem was just a lot of junk from a fresh rebuild on a block that probably wasn't cleaned all that thoroughly. New oil pump, new O ring on the pick up tube, fresh bearings, rings, lifters, NEVER EVER used a Fram filter in my life. Best first pass filtration in the Industry. Drops to near the bottom on subsequent passes. So unless you're changing your oil filter at every stoplight, buy a good one. WIX is probably the number 1 filter available. Personally, I use what came on it OEM. AC Delco. Have used Valvoline from day one. For almost 35 years now it's been Valvoline. Conventional until it's broke in and them switch to Max Life. My problem was caused by plugged up filters. Problem gradually went away with routine oil changes. Now when the pressure fluctuates even a little bit, I know it's time to change my oil.

3 of 3 people found this helpful.
130

I am having similar issue. I have already changed the sending unit , the filter underneath, ive flushed the oil added new oil and performance filter and still 0 pressure. Im lost!!

13 of 13 people found this helpful.
250

Thanks to all, for helpful info. I'll update where we stand now. Hubby is an old school mechanic, changes oil on time. My GMC Yukon XL is a 2005. I think someone here said there isn't a filter below sending unit before 2007? He has replaced the oil sending unit, and then months later cleaned the throttle body (he did not unplug or move butterfly) After a day or so, it gave warning signals. Then he decided to replace the throttle body. So far, 4 days later, no warning light. I think it is too early to tell. The RPM still idles at 600, and oil pressure drops to about 10, instead of 5 or less. Previously, if I drove about 5 miles and stopped at a couple of lights, generally the second traffic light would be when it would sound the warning. Altho in the last few weeks, I would occasionally get the alarm when I cranked up. I have been driving it primarily on long trips (1K roundtrip each month). Once I get on an interstate, make stops along the way, it doesn't ever have the warning occur. Hubby has been reluctant to replace the O ring and all of that. Said it would cost him (oh, me) $300, and could open up new problems since it is getting older. We are planning to sell it soon as I am looking for another newer Yukon XL. We want to get this fixed before selling it. I will update in a week or so as to the outcome of replacing the throttle body, before moving to the O ring etc.

1 of 1 people found this helpful.
40

I have an 05 Silverado 5.3 4x4 and have the same problem. So far I've removed the oil pan and cleaned out all the gunk, removed the oil siphon tube cleaned out the screen and changeg the o-ring, replaced the oil pump, changed out the oil sending unit, I didn't see the filter screen under the sending unit and the dealership verified this year model doesn't have one, i've also removed the valve covers and cleaned out all the gunk and made sure the drain back holes weren't clogged AND I've also changed the oil and filter numerous times and have even used sea foam engine flush but NOTHING has worked. I just bought an oil pressure test kit from Harbor Freight and my luck it didn't come with the right size fitting that will screw into where the sending unit mounts. As soon as I find the right size adaptor that will be my next step before an engine rebuild.

2 of 2 people found this helpful.
120

Has anyone ever tried a high volume oil pump to correct low oil pressure on one of these GM engines?

6 of 6 people found this helpful.
310

IF your problem is: Your oil pressure drops off after engine warms or it drops off and when you stop the engine and then restart it and pressure goes back to 40 for a few seconds and then drops to near zero again triggering indicators AND (important) when this happens there is NO additional noise from the engine....You have changed oil filters etc.. like religion..you most likely(no guarantee) have a clogged wire mesh filter UNDER the oil pressure sending unit behind the intake manifold on the back of the engine. I see these frequently. Its that simple on these engines folks. They do it all the time. I recommend going to your favorite mechanic and asking him to do this for you but if you are a DYI kinda person..do this to fix it. Start at the auto parts and buying a new manifold gasket set. I see people try to do this without removing the stuff on the front of the engine, trust me, do it!!! Finish in 1/3 the time doing it like this...Start by researching internet and get instructions for removing the Alternator and possibly loosening the AC brackets. (depends on engine and really only if it impedes removal of the intake manifold) How to remove the intake manifold bolts and fuel line. Your goal is to remove the intake manifold from your engine. NOTE:: If you are Houdini you may be able to remove the sensor without removing the intake manifold. Take a look first. The sensor requires a special socket to remove it because of the way it is made in some case socket is also available at the auto parts. Be careful with the sensor most likely it is working OK. Remove the sensor. Now take a long wood screw (3-4") and screw it down into the hold where the sensor screws in the block (screw it down into the wire mesh screen below the sensor) and then grab the screw with pliers and remove it from the block with the screen screwed on to it. Voila.. the problem is right there on that screw. Change to a new sensor? Up to you. Reassemble without that stupid screen...Good Luck.

4 of 4 people found this helpful.
250

Hi Mesquite Mike, sounds like you and I are on the same page. My husband the mechanic (by trade too) has done almost everything but the oil pressure test kit or doing it manually?.... In the meantime, I have a fix for the problem.... just bought a 2011 YukonXL Denali. I may have bought bigger problems down the road with all of the gadgetry! lol But I do want to get to the bottom of the problem on my 2005 YukonXL before I sell it. Let me know how things turn out. Thanks!

1 of 1 people found this helpful.
30

Same issue here as well. Changed oil pressure sensor, screen filter under sensor, Wix oil filter with high mileage Castrol. 08 chevy 5.3 has 170k miles and this is the second time this has done this. Planning on dropping the pan tomorrow and checking sump, o ring...etc...last resort will be full coverage, trusty helmet and a nice big oak tree at 30mph.

3 of 3 people found this helpful.
40

TexasRedbud, to be honest I didn't think to ask if there was one available for this engine. I can see how that might temporarily fix my issue but eventually I'll have to bite the bullet and change out the engine.

1 of 1 people found this helpful.
40

So I was finally able to hook up the oil pressure test gage and verify that at cold start up my engine oil pressure will rise to about 25psi and once my engine temp climbs to approx 200 the oil pressure has dropped to ZERO! Pressure will rise with engine RPM but it always returns to Zero when RPMs drop. I found a rebuilt long block (LM7) for just under $2K with a 3 year warranty and free shipping at engineguy.com On a good note, I did get over 200K miles on this truck with no other major problems so I can't complain all that much. Good luck to everyone!

250

That might be the only fix for my 2005, with the exception that I have the newer 2011 now (it was *only* a $30K fix!!!). I think husband/mechanic will put a new oil pump on the 2005.... did you try that? Or has anyone done so and it made a difference?

I've got the same freaking problem with the lifter tapping. Oil pressure sensor engine code occurred, whom tells me the sensor is bad and that filter may be clogged, which is why the lifter is tapping intermittently. After using engine flush right before the oil change, changing the oil and filter, the tapping only occurred two times for about 2 min each. Drove yesterday and no tapping at all. Tells me something is clogged with a bad oil pressure sensor. Sitting at Chevy right now getting the sensor changed. Hopefully, that's it, if not the next part will be that damn oring. If that doesn't work, that tells me the oil pump going, but highly unlikely that's the problem right now..

410

I sold mine after all the extra money spent. I couldn't deal with the issues anymore.

40

Fixed my problem for $2K, new engine runs like a champ

1 of 1 people found this helpful.
250

I "knew" there was a cheaper fix than buying another Yukon!!! lol I still have my 2005 and will still tune in to this page to see if anyone fixes theirs, short of a new(er) engine. But I am enjoying my newer one. Haven't made the first payment yet.....

1 of 1 people found this helpful.
250

Paul, one of my lifters on my 2005 is tapping about once a month. I will drive it around the neighborhood in the next week or so to see if it is still acting with the oil pressure drop etc. Since I bought another, it has been sitting. But it has been an excellent vehicle and everything still works great even the a/c. Only had to replace a couple parts on the a/c (resistor and actuator I believe) It doesn't appear that anyone has really fixed their oil pressure problems here other than replacing the motor?

10

I have on 05 Silverado with 270k on the motor...lately at start up I have zero oil pressure with the annoying ding ding ding going off...after rpm are increased oil pressure rises to about 40. I have already changed out the oil pressure sensor and new oil pump. I am buying a new sensor and removing the screen...hoping this fixes the problem...although I have severe tapping occurring from lifters too on drivers side...maybe time to remove valve covers and clean tappet guides.

1 of 1 people found this helpful.
120

Similar problem. 05 Sierra with 5.3l 220k miles. Pressure never gets over 40 PSI and most of the time the low pressure is 20, even after warm up. One of my symptoms that puzzles me is that the gauge ( a mechanical one for now) bounces around. Another that puzzles me, if I pick up the RPM's, I can get 40 PSI, but once the lifter starts ticking, the 40 PSI will not pump up the lifter. Based on my past experience, it should. At this point, my plan is to drop the pan, check rod bearing clearances, replace oil pump, and pickup tube o-ring. While this plan seems sound, I have seen several comments here about new oil pumps ( and o-rings I guess ) have not fixed the problem. Maybe I do have a failed lifter, but if so, why will 40 psi at startup quite the lifter, but 40 psi after warm up not do the same thing?

1 of 1 people found this helpful.
310

oil viscosity changes as temp goes up...IE: 10W40 (over the temp range) the pump flow changes dramatically at temp also the thicker oil slows at RPM and the combination of the rocker hitting that lifter faster with RPM doesn't allow it to pump up. In your case its back to the pump for me because of what you said abut the guage..

1 of 1 people found this helpful.
35

I have a 2005 Tahoe with a 5.3L. It has the lifter ticking when first started and normal oil pressure, The ticking keep s going for about 5 to 10 miles until it warms up. During this time the oil pressure gauge never goes above half way. After the motor gets good and hot the lifter tic goes away and the oil gauge then goes above half way and starts to move with the engine RPM, as it should. I tried an engine flush and marvel mystery oil but it doesn't seem to have made any difference. The truck has great power and acceleration. I don't believe its rockers or push rods because the noise goes away. But after the ticking stops and if I pull up to a store and let it idle while I run in, when I come out it is ticking again, but stops as soon as I start driving again for about 20-30 secs.. I have noticed that during the time after starting it and driving while its ticking, if I come to a red light I have seen the pressure drop to the warning lvl. but that has happened only a few times. Any help with this issue would be greatly appreciated.

3 of 3 people found this helpful.
10

I had the same problem with my truck. It is a 2007 GMC Sierra with a 5.3. Try the screen under the sending unit. You may have to remove the intake to get to it but under the sending unit is a screen that if it gets stopped up will not allow the sending unit to read correctly. Also try flushing the engine when changing your oil to remove a lot of the sludge if your engine has a lot of miles. If this doesn't work try the oil pump.

1 of 1 people found this helpful.
20

i have a problem with 07 chevy suburban 5.3l 180k..oil pressure gauge stopped working on friday..called a mechanic friend..asked him what to do..if possible was i able to drive in town(live in a small town)..vehicle was not pinging..ticking.smoking..overheating...he said yes just don't drive to far and if it starts pinging stop immediately..drove for a couple of days around town..looked up what might be wrong,,oil pressure switch/sender..went to o'rielly;s and picked up part and socket to remove it..drove 35 miles in vehicle to pick up part..changed yesterday...real bitch to change...got everything put together..disconnected battery to reset computer..started vehicle and oil pressure gauge still didn't work and oil pressurelow stop engine light came on...don't know what to do next ???

2 of 2 people found this helpful.
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I had this problem on my 2008 Silverado at about 105,000 miles and this thread really got me going in the right direction. However, no one is mentioning the fix I did that was recommended to me by a friend who is a Chevy parts dealer and sees this problem a lot. My symptom was as others have described. Shortly after startup, the oil pressure gauge drops to near zero, then bounces back up again and displays the message to stop the engine.. My truck was running fine in all other respects so I drove it home from the mountains, watched the oil pressure and it was stable for the several hour drive home. I never saw the message at highway speeds. When I got home, I saw the problem several times shortly after starting the engine, within a few blocks. My friend said it is probably a problem with the screen. However, he said there are other screens on the oil lifter assembly and that should be replaced along with a new oil pressure sensor. I have done that and that seems to have completely solved the problem. The screen itself is not user serviceable. There is no part number for this screen. Just popping it out seems like a bad idea. To get at it, you need to remove the intake manifold. I had never done this before but it wasn't difficult. It was just time consuming because of all the connectors and lines you need to take off as well as removing the alternator. Underneath the intake manifold is the Oil Lifter assembly. The oil sensor attaches to this assembly. Once the intake manifold is removed, the oil lifter assembly is really easy to remove and replace. There are no serviceable parts on the oil lifter assembly, including that screen (except for the gasket that can be re-used, but comes with the assembly). I examined the screen on the old assembly and honestly it didn't look too bad. So that makes me think it's not as simple as others have indicated. The parts list is as follows: 1) New Oil Lifter Assembly 2) New Oil Pressure Gauge 3) New gasket set for intake manifold (old ones can't be re-used) I am really glad I did the whole job as described, because removing the intake manifold is not really something I want to do again. So while you're in there, you might as well put new parts in. I hope this helps some else.

3 of 3 people found this helpful.
250

Here is an update on my 2005 GMC YukonXL oil pressure problem. As stated above, my husband replaced the oil pressure sensor (according to some here and schematics I believe, there is no filter screen under it in the 2005). He also replaced the throttle body a month or so later. After doing all of this we still had the problem of the oil pressure dropping. He has now replaced the oil pump with a high volume oil pump and O ring. He said there were 3 different color/size O rings and it appeared that the orange'ish colored one was the one he removed and replaced with the same color. He said the old O ring was rather hard. After doing this work, I am happy to report that the oil pressure is 60-65. It appears to be fixed now. I bought a 2011 and am not driving the 2005 enough to say that there are no further problems but it has been running well when it is driven. I hope that this helps others with the same problem. In and older model with 200K, I think I would start with the oil pump and O ring first to see if it fixes your problem.

5 of 5 people found this helpful.
70

Update on the status of the fix after replacing oil lifter assembly, oil pressure sensor and oil change on my Chevy Solvetado 2008 with 105,000 miles on it. The problem seems to have been fixed completely. Did a round trip to mountains since fix and been driving around town. Pressure gauge is behaving much better. It never drops to as low as I was seeing and is showing higher than 40 under acceleration. I wonder what this oil lifter assembly does? If it is failing, I wonder if it doesnt move oil around lile it should? Maybe there really was a pressure problem? Of course it could have been the sensor failing as well. I am leaning towards the screen not really being the problem in my case. It really didn't look dirty or clogged. Chris

4 of 4 people found this helpful.
70

Upon further reflection, I am certain the only problem I had was a flakey oil pressure sending unit.

10

2007 Chevy Silverado K1500. I had the same problem; fluctuation oil pressure and would drop to zero and tell me to shut the engine down. The oil level was good, and was still at 25% oil life with about 6 months since the last change. Someone said that the oil filter may be clogged or have sludge in it. I went and got my oil changed and the problem has since gone away. Hope this helps.

1 of 1 people found this helpful.
250

My problem ended up being the oil pump and/or O ring. My husband is an old school mechanic whom changed my oil meticulously on time.

4 of 4 people found this helpful.

Just seen this we just bought a 08 Suburban LTZ with the 5.3 160k... The check engine light was on when i test drove it oil pressure seemed ok though well they told me they ran the codes and it was a evap code and there repair shop would fix it no problem so i bought this thing and being a ex ase tech i decided to run the code my self when i got home it was just bothering me... So of course it was on for low oil pressure so i called there shop which told me they cant get it in for another week so im waiting on that i decided to just go get the filter and spending unit and change the oil at the same time with good oil and a good filter really wasnt bad to change just removed the pcv hose and fuel line got right to it... Well after pulling the sending unit i found some one has already removed the screen so i went ahead and installed the new pressure sender and changed the oil... Well at start up has around 60psi and slowly as the temp rises dropes to about 5 to 10psi on a mechanical gauge... I do know the pressure stays around 40psi while driving but as soon as you stop its down low and im prety sure i can hear some lower end noise every now and then once warm and idling for a little bit...Sure there gana try to screw me on this also seeing as it was bought as-is... Gana see what they will do for me since they said theyvwould fix the problem the light was on for then might try a new oil pump next if they dont help...

20

What if you had the ac/heater blower motor repaired under neath the dash and right after that you get the "low oil pressure turn off engine" light on. Can a oil gauge malfunction be a possibility and related to the blower repair? Is it possible that a wire was knocked loose or something to that nature? I'm having the same problem and it happened right after the blower repair. I've already changed the sensor switch and I still have the same reading on the dash. Any insight would be very helpful. Thanks.

2 of 2 people found this helpful.
90

I had a Similar oil pressure problem. We bought a 2008 Suburban 1500 5.3 AFM (active fuel management), 4 wheel drive, with 183k this past December from a private seller; we met at a local Walgreens (mistake #1), and then I discovered a few days later that I had oil pressure problems. The first problem was that when the temperature dropped below 10 degrees (I live in Minnesota) the pressure would drop to 0 when I would start the vehicle in the morning. In order to keep the pressure up I would need to nurse the rpm until the engine warmed up a little, then the psi would stay above 20. The second problem was that I could not get the pressure past 40 psi no mater how high I ran the rpm, that is until the motor was completely hot. I would see the pressure slowly rise while driving on the freeway until it was finally up to 55 psi when the rpm was above 2500. This would usually take 20 minutes. At normal cruising speed the psi would run around 38. I also had a pretty loud lifter until the motor was heated completely and then it would quite down. Steps followed to fix the problem: 1) Researched on the internet (mistake #2). 2) Purchased an oil pressure sensor and AFM filter srceen. 3) Researched Alldata and realized my problem wasn't likely to be caused by the screen or oil pressure sensor (AFM worked fine). 4) Replaced screen and sensor anyway since I had them. 5) More research (problem not solved by step 4). 6) Purchased pickup tube o-ring and oil pan gasket and assembled tools (mistake #3). 7) Pulled the pan then realize that I never wanted to do that again so I went to the local dealer and purchesed a AFM oil pressure relief valve (located in the oil pan) for $13. 8) Replaced the o-ring, AFM valve, reinstalled the pan replaced the oil filter, added oil, started the engine (before re-installing the front differential) and watched the gauge go right to 60 psi (whew). The oil pressure is now acting the way I would expect it to; starts out high, drops a little as the engine heats up, fluctuates with rpm. I still get a little lifter noise at first but it quiets down after a couple of minutes. Lessons learned: 1) When buying a used GM truck (or any vehicle), always be the first to start the vehicle in the morning (ref mistake #1). The Suburban was completely heated when we test drove it so everything seemed great. I don't know if the seller purposely deceived us, I like to think not, but I will never buy a used vehicle again unless I get the chance to cold start it. 2) Research on the internet is great (ref mistake #2) but be careful, there are a lot of good intentions and a lot of bad advice. If an AFM screen is getting plugged by sludge & crud, it's doing its job, don't delete it from the system; there must be some other problem, I didn't have any sludge in my screen filter or pan. 3) Do the job once. I'm not sure if replacing the AFM valve helped but for $13 it didn't hurt and I will never need to pull the pan for this issue again (at least not on the vehicle). 4) Have the proper tools (ref mistake #3). If you decide to do this yourself and you have a 4 wheel drive, buy/rent a transmission jack or buy a transmission jack adapter for your floor jack. I used an ATV jack to drop and install the differential and it made the job so much harder. Some people lay on their back and muscle the differential out and back into place but I'm past that age. I hope my experience helps.

9 of 9 people found this helpful.
120

So i have solved my Lifter noise / oil pressure problem. I installed a new oil pump, but the old one looked fine and was not the issue. I am convinced the O-ring on the oil pump pick up tube was allowing air to be pulled into the oil system. The oil/air mixture would have low viscosity that would allow the lifters to leak down and rattle after the engine was warm. This type of air leak on the oil suction tube could cause all types of problems.

5 of 5 people found this helpful.

Maybe mine is a slightly different problem because I replaced the sending unit and the intermittent low oil pressure issue seemed to disappear. But then returned. Mine APPEARS to be electronic. I say that because if goes from normal to zero in a fraction of a second then back to normal in a fraction of a second. The needle jumps. If the pressure was indeed zero and building back up the needle movement would be slower. As far as clogged screens, I cannot see how the needle would not go low and remain low.

90

Could be the step motor. I know there was a problem with 2006 and older. You can buy them and replace yourself or send the instrument cluster in for repair. Clouis

Yeah I soldiered new ones in my 03 couple years ago. They went out one by one. This one is acting differently than each of those that went out but I will keep that on my list of potential things. Thanks

So my issue is that at various times, or not at all, my oil pressure gauge will go to near 0 and the oil light comes on with the alarm bell ringing. I can run this for 1 mile or 10 before the problem starts and when it does it stays in this condition until it is shut down. No engine noise, no tappets or anything, just that ringing...or not. Oil and filter just changed and no change-- it's being suggested that I replace the engine...seems a rather strong reaction to this problem, or is it?

250

Your problem sounds like the one I had on my 2005 Yukon XL. We changed the oil pressure sensor and cleaned the throttle body, working through possible fixes, before finally changing the O Ring. I didn't have anymore problems after that, before I sold it a month or so later. Bottom line, the 3rd try may have fixed it. So I would suggest starting with the O Ring. (see my earlier posts above)

1 of 1 people found this helpful.
250

Update: Mechanic hubby put a high volume oil pump and also a new O ring on the pickup tube. After that, the pressure was always high, I think around 65 lbs. I also had a lifter(s) rattle about once a month. After replacing the pump and O ring I didn't have any further problems for the month or so that I kept it. Primarily my oil pressure would drop down to less than 5 lbs after I drove it a mile and then I would spend my time at red lights with my foot on the brake revving the engine to keep it from about shutting off.

2005 Suburban STARTS at 0 pressure will rise when driven but idles at about 10. Changed oil and recently had pan gasket and that o- ring done so going to try sensor next?

Hi Sin_T_Ter. I am basically having the exact same symptoms and same year truck. What fixed it for you? I am hoping you say it was a faulty stepper motor in the gauge.

Mine went back to normal after changing the oil 3 or 4 times in a month and using only good ACDelco filters. Also put Lucas in it. I think it was just sludged up.

10

First off this problem is a gold mine for chev and gmc maintenance departments. Drivers of these 5.3 engines experience the problem and the majority bring it to our dealers and they tell us the "book" says it takes 2.5 hours to replace plus parts. Our son took his to the dealer and they charged him over $500 I was fishing with a retired gym mechanic and he told me he could change the gauge in 15 minutes. I got mine done by a non gm shop and it cost me $100 for labor and parts. After I replaced it I had problems again and he told me over the phone to go to an auto parts store and get an engine oil flush and put it in 5 minutes in a hot running engine before they drop the oil out. I went to Napa and got their brand plus a wix gold filter and changed the oil and it has been perfect since. I'm going to do it at my next oil change as well . I have 158k miles on my truck. When you google a mechanic that tells you how to do it he got it done in 17 minutes. This is a flat out rip off by gm dealer repair departments.

1 of 1 people found this helpful.

I ended up putting a mechanical gauge in and ran it into the cab. as many times as the motor lost pressure and wasnt making any noise i was sure it was either the gauge or pressure sensor. it finally tanked and mechanical gauge stayed up. so i just drove home and ordered a sending unit. that damn ding ding ding drove me nuts for the 20 min drive home.

Will the screen Clog cause valves to tick?

300

It could but it's important to keep it in. It protects the small passages from getting clogged. It's purpose is for the management system that cuts off 4 cylinders during light throttle

I have been dealing with the low oil pressure on my 08 silverado for many months. Replaced the sending unit and screen didn't work ran eng cleaner didn't work tried oil additives didn't work tried turning volume up on radio didn't work what did work and I believe this is the correct fix after reading many answers drop the oil pan and replace the oil pump pickup tube o ring. It was hard as a rock and broke apart when I touched it.Oil pump was good. Oil pressure is now 40 psi at idle 60 psi at hwy speeds.

My 2012 5.3L Silverado with 130k had the exact same issue described on this thread. This is what happened to me and how it was resolved. I got the low oil pressure signal while at highway speed, stopped, checked oil(Full), no engine clanking so I carefully limped it home, stopping several times when the pressure returned to zero. It would jump to normal after stopping for a while. I could get about 4 miles out of it. I changed the oil pressure sender and screen at home. (Its hard to get at, but it can be done easily with a proper set of tools including a oil pressure socket) Ran fine for about a week, then the low oil pressure returned and worse than ever. I foolishly took it to a dealer to have the 'experts' check it out. They called me back later. They had attached a mechanical gauge at the top of the engine and also at the oil filter. They confirmed that the oil pressure at the top of the engine was sliding to zero, but the bottom gauge was normal. They said "we're not sure, but some sort of pressed fitting rotated in your engine and YOU NEED A NEW ENGINE". I luckily called BS on that and told them I wanted to know what "pressed fitting rotated". They couldn't tell me even after I talked to the GM district manager. It all sounded fishy so I picked the truck up and drove it home. Had no problem with the oil pressure in about 20 miles. I started talking and asking around using the internet a lot. I got some things to try. This is what has cured the problem for me: - I flushed the engine with a 5 minute crankcase flush, I think it was called 'KW 5 minute flush' - Full oil change using Mobil 1 full-synthetic 5W-30 - A Mobil 1 oil filter, a M1-212. This is a larger filter than is specified. The advice to use a larger filter came directly from a GM technical bulletin. I have had no problems since this was done about 2000 miles ago. I believe the problem is solved. An interesting point is that I had no more problems after picking up the truck at the dealer. When I arrived home, I noticed that they had replaced my Fram oil filter with a larger ACDelco filter, A PF63E. I believe the low oil pressure issue is related to the size/capacity of the oil filter. Don't ask me how, but GM recommends a larger oil filter in these vehicles now. Also, I was using Valvolene Max-Life 5W-30 synthetic blend oil. I don't believe this is an approved "Dexos -1" oil anymore, it was when I started using it, but it is not anymore. I am switching to Mobil 1 full synthetic. Another small interesting piece of information is that before all this my fuel mileage was dropping from about 16.5 mpg to 15.2 mpg's. After all this fiasco, and changing the TRANSMISSION FLUID, my mileage instantly went back up to 16.5mpg's and is still climbing! The AFM switches to V4 mode much more often. So here is my advice if you are experiencing low oil pressure: Replace oil sending unit and screen, Flush, change to full synthetic oil and most importantly, use a PF-63E oil filter or equivalent. I hope this post is of some help.

Have not read any issues similar to mine but will share for anyone that might recognize the symptoms. 05 Silverado 5.3 Smoked (past tense) horribly when first starting with new pressure sensor installed. No screen in place under the sensor. Reinstalled the faulty sensor -- no smoke! Tried another new sensor with same results. After probably 4-5 times trying to use a sensor and referring to several mehanics I finally Installed a mechanical oil pressure gauge ,but the truck lost all pressure at stop signs and would barely cripple across the street before building enough pressure to stop rattling. Took off the tube to the mechanical oil gauge (@ the original location of the oil pressure sensor) and installed a short piece of iron pipe with a cap on top. Runs great. No smoke. No rattle. Also, have no idea what the oil pressure is. My truck has 285k and runs strong. In a way, I hope this does not encourage anyone to copy my approach, because I'm sure this is the worst possible action a person could take but it produced miracles for me and now after about 5 months later still drives great.

Just in case some people are scared of a rebuild looming... I have a 09 Silv NBS 5.3L. Motor has burned oil since day one. I do oil changes every 17,000 - 23,000 per oil life monitor (crazy i know). I have pulled a 7k lb trailer over 100,000 km of trucks life. Truck has 481,000 km on it currently on original motor and trans (trans oil change every 120,000k). I have the same problem with the oil pressure sensor on and off pressure. It seems to be worse if I do not use Valvoline maxlife for some reason and do not know why. This really limits my choices for oil changes while on the road. I have ran this truck out of oil, started it on fire, ran with percieved no oil pressure for over 6 hours at 80 mph pulling a sled trailer through idaho and montana. Truck still runs fantastic and does not burn any more oil than it did since new. Anyway, I will check this filter again, as I paid someone to change it but problem still persists off and on. Motor is does not make any ticks or knocks so i know it has to be oiling especially since I have been running it like this for a couple years now with out being able to fix the problem. Will run months with out issue and then pressure will drop while driving and return as fast as it dropped. Would there be any other cause for this besides the sensor filter?

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