"Low Engine Oil Pressure" Do I really need a new engine?

What tennisshoes said.

I'm just baffled a little by how the only fix is to get an entire new engine

Would that be cheaper than replacing the whole thing?

Thanks a lot, you've given me some comfort in my engine problems

Try a high volume oil pump first

you can test your oil pump.remove it and test it for wear

If you want to budget fix it, you can replace the rod bearings and oil pump. I inspected my main bearings and they all still had the white coating on them. But the rod bearings were shot. I had zero oil pressure at idle when hot. I first just replaced the rod bearings but it still had low pressure so I went back in and installed a stock pressure Melling oil pump. Now it idles at 25lbs hot idle and 42lbs highway. If you your crank journals are in good shape you can put new bearings in. Might as well replace the rear main seal while you’re in there, regardless if it’s leaking or not. Replace it. When you replace the bearings YOU HAVE TO BREAKE THEM IN...... Just like if it was a new engine. People that do this and trash the new bearings are driving their Jeep/car like before they put the new bearings in and ruin them. You need at least 500 miles on the new bearings before you horse beat it. I’ve done this on 3-4 cars in my life and all were fine with no issues. My 1990 XJ 4.0 has new rod bearings, seals and gaskets and runs great. Not a drip and I now have 5000 miles on the bearings at 25 hot idle and 42lbs driving. If it doesn’t smoke and the journals look good it can be done. Less than $100 and some elbow grease and you will be good to go.

If you want to budget fix it, you can replace the rod bearings and oil pump. I inspected my main bearings and they all still had the white coating on them. But the rod bearings were shot. I had zero oil pressure at idle when hot. I first just replaced the rod bearings but it still had low pressure so I went back in and installed a stock pressure Melling oil pump. Now it idles at 25lbs hot idle and 42lbs highway. If you your crank journals are in good shape you can put new bearings in. Might as well replace the rear main seal while you’re in there, regardless if it’s leaking or not. Replace it. When you replace the bearings YOU HAVE TO BREAKE THEM IN...... Just like if it was a new engine. People that do this and trash the new bearings are driving their Jeep/car like before they put the new bearings in and ruin them. You need at least 500 miles on the new bearings before you horse beat it. I’ve done this on 3-4 cars in my life and all were fine with no issues. My 1990 XJ 4.0 has new rod bearings, seals and gaskets and runs great. Not a drip and I now have 5000 miles on the bearings at 25 hot idle and 42lbs driving. If it doesn’t smoke and the journals look good it can be done. Less than $100 and some elbow grease and you will be good to go. My Jeep XJ 4.0 has over 200,000 miles on it.

First replace your oil pressure sensor. It is located just above the oil filter and is a common problem. I was getting low and no oil pressure readings on occasion. My mechanic charged me about $120 parts and labour. Now it reads sixty. '98 Cherokee 4.0L

So my name is Jade and get a new engine is not the only answer number one you can get the oil changed and try using like a 2050 on the oil it's thick enough a lot of times it'll help with oil pressure you also have a sending unit and you also have a sensor that can be checked before you go to that extreme and I have some other handy hints I have an 04 Grand Jeep Cherokee limited edition you know like a way to reset your service light so you coming so my name is Jade and getting a new engine is not the only answer number one you could get the oil changed and try using like a 20 fifty on the oil it's picking up a lot of times it'll help with old pressure you also have a sending unit and you also have a sensor that can be checked before you go to that its train and I have some other handy hints I have no for rent you Cherokee Limited Edition you know like a way to reset your service light and a few other things so you might want to look for my youtube channel coming but this should be a good answer in itself I hope it helps a lot of people and it will

I have a 2003 Overland Grand Jeep Cherokee 4.7l V8 and also had low oil pressure problem. One of these websites suggested to replace the oil sending unit located above the oil filter. Did that and still had low oil pressure at idle. Another site suggested to blow out the oil galley by removing oil sending unit and cranking the motor just in case of any blockages. Did that too but what a mess that makes, still did not do the trick. I then had my radiator replaced because there was a water leak and still did not help. We then discovered that the thermostat does not open and hence the reason for the low oil pressure. Oil gets to hot and therefore the oil pressure drops when car is hot and idling. Had thermostat removed and had since not had any problems with oil pressure.

If you still have decent compression, you can drop the oil pan and replace the oil pump and rod bearings. In most cases I’ve seen that the crank bearings were fine, but I check the crank bearings I can get to, to make sure.The rod bearings wear the most out of everything. (((JUST REMEMBER))) If you do this, there can be no scoring or major damage to the crank bearing surfaces and you have to break the the new bearings in like it is a rebuilt engine. Drive it mellow for 500 miles until the bearings seat in. I have done this on a few engines and never had a problem. The last two I put over 10,000 miles on them them with zero problems and they both had great oil pressure. Replace the oil pump, don’t cheap out, I did once and had to pull the pan again to replace it. They wear out too.

I have a 98 jeep Cherokee. The oil pressure Gage works sometime n sometimes not. When it does it goes from the first mark to the middle. I put new switch on it n steal the same

I had exactly the same problem. It finally stopped working altogether. I checked around and found that this is a fairly common problem. It is caused by a malfunctioning oil pressure sending unit. It is easily replaced and fairly inexpensive. This fixed the problem and I now get consistent, accurate readings.

2001 Grand Cherokee, with the same problem. Very low oil pressure at idle. It's fine until the engine really warms up, then it drops, and the warning light and bell come on (and it gets hot here in Dallas in the summer). The engine isn't running hot, though - the temperature gauge shows normal temperature - never above the middle mark, even a little below. Have replaced the sensor twice, and replaced the oil pump. Made no difference. Tried a heavier grade of oil. Made no difference. Car only has 132,000 mi. on it, always had regular oil changes with synthetic oil. Hard to believe there could be any worn engine parts that are causing the pressure drop. The pressure drop also started happening over a relatively short period of time, not slowly over an expended period. There are no unusual noises coming from the engine at this point - runs and sounds just fine. Pretty strange. It isn't worth dumping a lot of money into doing any engine rebuild. I'll try the 20/50 heavier oil someone suggested above, and see what happens. Otherwise, I'll probably just keep running it until the engine gives up.

2000 Cherokee freedom, having the same problem. Good pressure until it warms up, them drops it's whole ass out the gauge. When I bought it, we went to a shop and talked to a tech, he said he put the scanner to it and it read a malfunction on the oil pressure sensor. (IDK why, when I could have drove 30 miles to my own shop and done it myself, but whatever). I replaced it and nothing. It's a beautiful jeep considering the circumstances that it now has a notable knock from it getting worst every day. So, my question is, are there any string 4.0 L-6 242 around at a fair price for an average Joe working man? It's my daily driver so I need something reliable!

I replaced the oil sending unit, then the rod bearings and oil pump, then ran 15w-40 rotella oil. My 2000 Cherokee 4.0 still showed 0 oil pressure at idle, so I gave up. I have put 15000 miles on it since I gave up, including a 5500 mile road trip. If it blows up I'll buy a new one but until then I'll save up for the LS swap

Hi ModRod... I am having the same above issue. Would you be willing to check and do the fixes you suggested if need be for a charge?