Coolant Leak


Asked by Jun 02, 2015 at 12:48 AM about the 1999 Chevrolet Blazer 2 Door LS 4WD

Question type: Maintenance & Repair

Long story short, recently bought a used 1999 Chevy Blazer for a decent price.  Its mostly in good shape, but noticed a coolant leak almost immediately.  Mechanic buddy was with me when it first happened, briefly looked at radiator and that did not seem to be the problem.  Talked to previous owner and he said he just replaced the radiator block.  

The leak seems to only occur after driving and parking (turning off), after ~10 mins for about a 5-10 minute period.  Sometimes it leaks, sometimes it does not.  It has been up to maybe half a litre, especially if parked with the front inclined downhill slightly.  There appears to be two spots where the leak comes from, more comes out of the left side under engine (photo included).  It's typically a steady drip.

I did some research and sounds like a water pump issue, but I am not a mechanic at all so need some advice.  If it is, where exactly is this plastic cover underneath that I can supposedly check (I don't want to start unscrewing the wrong thing)?  And how long can I hold out before replacing the water pump?  I can buy a new waterpump for $80, but finding a buddy with the time to replace it is the problem.  


10 Answers


Hello, What engine?? 3 major areas on S-10's... Water pump, Intake Gasket between manifold and heads, Rear Freeze Plug(s) That sure looks like a water pump leak/heater control valve to me. Don't dare waste time replacing whatever is wrong...S-10's love head gaskets don't want to run her hot! Good Luck-- AskTrannyMan

3 out of 3 people think this is helpful.

Looks like the water pump and possibly the upper radiator hose (at the radiator). HTH. - Jim

3 out of 3 people think this is helpful.

Engine says 4.3L. I notice the engine has a lot of coils and etc mounted on top of it, how hard would it be to change the head gasket? Also, I have few different sized gaskets that I bought for my old 1999 Malibu but Im not sure if they would fit on this engine (those were supposed to be used to stop an oil leak, so maybe a different type of gasket). As you can probably tell, I don't know much about vehicles. My training is in a different field :P


Hello, No, the head gaskets are different...and yes, I thought you specialized in another Field! Good luck, and get her checked out...don't worry about head gaskets now...I doubt you have that problem yet. Hope this Helps, AskTrannyMan

2 out of 2 people think this is helpful.

lol ok. The thing is that I had a Malibu and the engine kinda blew up. Shop wanted $1300 to fix it so I scrapped it and bought the blazer for a fair price. Cousin of mine had to get a waterpump changed in her car (albeit a Sunfire), and the shop wanted $1300 for that fix. I just want to be certain because I'd rather just buy the waterpump, and rent a mechanic friend for a case of beer and some smokes for a much better price. Since you're a "TrannyMan", the other main issue with the Blazer (which was why it was cheap) is that the 4x4 apparently engages, but doesn't stick properly (apparently bounces around on the socket). Previous owner said something about a loose socket, then said something about installing a new transfer box. Do you know how intensive or costly it would be to replace the transfer box? Also, would this affect the 2WDr at all if not fixed in due time?


Hello, Wow, 1300 for a Pontiac Job...where do you people live??? I really don't know enough about the 4WD without looking at them... That doesn't score with me "socket", but maybe Jim will chime in. Usually the answer is "No" to using just 2WD, as long as the carrier is not fried, and the driveshaft u-joints are OK. That water pump job w/ parts should be no more than 300 at a reputable shop. Good Luck, AskTrannyMan


PS: You can get more work out of friends with beer and LEFT handed cigarettes... >>(())<<


Actually I am in interior British Columbia, Canada. I didn't realize that there was a Canadian version of this site until now, but whatever it's not like that makes the mechanical problems any different. Anyway I never tried the 4WD myself simply because with my luck, it would get stuck in that messed up position. Also, it is an automatic 4WD button, if that matters.


You need to see what happens when you try 4x4. The blazer has multiple thing that can cause problems. Never heard of a socket being loose, lol.

1 out of 1 people think this is helpful.

Hey so I figured I should provide an update. Brought the Blazer into a shop today and turns out there was a crack in the radiator, so that got fixed up. Waterpump did not seem to be the issue. The crack was near the top of the rad (though you'd have to remove it to see it), so the inconsistent leak was probably due to whenever there was enough pressure to push the coolant up to the crack. As for the 4x4 problem... Buddy and I tried testing it out and basically you could feel the 4x4 trying to lock into place but couldn't. The 4x4 is automatic, via a few buttons on the dash. I thought that maybe it could have something to do with those buttons, but not sure. Also, after taking it out of town I noticed that the left tire became unaligned somewhat, sometimes making funny noises. Also the ABS light was on ever since I got the Blazer. Did some research and realized that it was probably the bearing in the left side, which requires a new hub replacement. Tried to get the mechanic to do this replacement today but they wanted like $500 to do that, and they were more concerned about replacing the ball joints. I know that the previous owner just got a ball joint replaced back in May. So either the shop was shady, the previous owner was shady, or the bearing/hub issue wears down ball joints very badly. I ordered a new hub for around $200 so I'll just install it myself when it gets here. The shop scanned the engine warning issue and showed me codes for oxygen sensors and "engine misfire". The mechanic told me that the misfire could be anything so they would need to tune it up (more $$$ obviously). After some basic research, I learned that scanners should be able to explain what the precise problem is, so I went ahead and ordered one for myself. Another issue I have that I hope I can resolve easily is that the radio antenna is not connected to the stereo. I tried taking the stereo out with someone else, but couldn't make sense of all the cords at the time (it is wired for satellite radio which I don't have or want).

Your Answer

Add photo

Related Questions

  • Coolant leak 2 answers

    I recently bought a 2003 chevy v6 vortec blazer. And when going to change the oil I noticed I was leaking coolant. It didn't leak to bad at first but by that time the next day I had taken it over ...

    2003 Chevrolet Blazer 2 Door 4WD


    Maintenance & Repair

  • 03 Blazer leaking coolant 3 answers

    I have an 03 Blazer with a brand new radiator. It has been running fine as far as that goes until last night where it overheated and started smoking. I found coolant sprayed over the undercarriage...

    2003 Chevrolet Blazer 2 Door LS 4WD


    Maintenance & Repair


    2003 Chevrolet Blazer 4 Door LS


    Maintenance & Repair

  • Car leaking and running hot 13 answers

    My car started leaking all the coolant fluids looks like from behind the altenator i have a 1996 chevy blazer and my temperature gauge never reaches hot but the truck smokes from the same area th...

    1996 Chevrolet Blazer 4 Door LS 4WD


    Maintenance & Repair

  • car leaking coolant into floorboard 1 answer

    1999 Chevrolet cavalier is leaking coolant into driverside floorboard

    1999 Chevrolet Cavalier 4 Dr STD Sedan


    Maintenance & Repair


Looking for a Used Blazer in your area?

CarGurus has 1,117 nationwide Blazer listings starting at $1,995.


Search Chevrolet Blazer Questions

Chevrolet Blazer Experts

#1 Andrew Olsen
Andrew Olsen
Reputation 1,920
#2 yetilikesbeer
Reputation 1,210
#3 Rowefast
Reputation 920
View All

Related Models For Sale

Used Chevrolet Tahoe
611 Great Deals out of 27,555 listings starting at $600
Used Chevrolet S-10
3 Great Deals out of 1,393 listings starting at $1,995
Used Chevrolet Silverado 1500
1,982 Great Deals out of 160,214 listings starting at $1,995
Used GMC Jimmy
231 listings starting at $999
Used Ford Explorer
744 Great Deals out of 74,481 listings starting at $750
Used Chevrolet Camaro
136 Great Deals out of 35,100 listings starting at $1,995
Used Ford F-150
2,397 Great Deals out of 210,250 listings starting at $895
Used Jeep Grand Cherokee
844 Great Deals out of 69,767 listings starting at $700
Used Chevrolet Suburban
384 Great Deals out of 18,545 listings starting at $2,395
Used Chevrolet Impala
543 Great Deals out of 28,509 listings starting at $700
Used Chevrolet C/K 1500
859 listings starting at $2,500
Used GMC Yukon
406 Great Deals out of 16,271 listings starting at $1,800