I have replaced the sending unit, hooked up a mechanical gauge, and replaced the oil pump. The motor still has very low pressure. I know I'm on borrowed time. I was curious if the thicker oil would even help the motor limp along a little further than the thinner 10-30 oils?
Worn Engine
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Originally Posted By: expat
You have come to terms with the fact ' you are on borrowed time' So why are you reluctant to use a thicker oil to bring your oil pressure to an acceptable level?
I'd jump in with a 15 w-40 or 20 w-50 or add a bottle of STP or other Thick additive to what you have, to keep the mill running.
Going the 20w50 / STP (1/2 bottle per change) route kept a motor I had with bad bearings going for over 40,000 miles. I changed the oil every time the pressure started dropping again and the noises got louder. My mechanic bought it and he said the only thing wrong was the bearings. he changed them and ran the heck out of it. That was a 1976 232V6 (3.8) Good Luck
You have come to terms with the fact ' you are on borrowed time' So why are you reluctant to use a thicker oil to bring your oil pressure to an acceptable level?
I'd jump in with a 15 w-40 or 20 w-50 or add a bottle of STP or other Thick additive to what you have, to keep the mill running.
Going the 20w50 / STP (1/2 bottle per change) route kept a motor I had with bad bearings going for over 40,000 miles. I changed the oil every time the pressure started dropping again and the noises got louder. My mechanic bought it and he said the only thing wrong was the bearings. he changed them and ran the heck out of it. That was a 1976 232V6 (3.8) Good Luck
Originally Posted By: wally6934
If you know the oil and filter history of this jeep it would be nice if you posted it so we could all learn something. 150K miles is much to short for an engine to wear out, maybe you could help one of us avoid the same problem.
It could have been a defective set of bearings from the get go, may be even overtightened caps from the factory. Stuff happens. He said he replaced the pump. Maybe it was weak for a while, providing insufficient pressure but not low enough to trigger a light or be so low he would notice on the gauge... Just guesses from different experiences.
If you know the oil and filter history of this jeep it would be nice if you posted it so we could all learn something. 150K miles is much to short for an engine to wear out, maybe you could help one of us avoid the same problem.
It could have been a defective set of bearings from the get go, may be even overtightened caps from the factory. Stuff happens. He said he replaced the pump. Maybe it was weak for a while, providing insufficient pressure but not low enough to trigger a light or be so low he would notice on the gauge... Just guesses from different experiences.
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Originally Posted By: OVERK1LL
Originally Posted By: Zaedock
If you do in fact, have 0 oil pressure, replace your oil pump. I'm a Jeep guy - have 2.5L and 4.0L rigs, a 4.0L buggy, and work on friends Heeps. In my experience, the average factory pump life is about your mileage. Also, IMO, the factory Jeep upper oiling has never been super. I usually add a high volume pump with either a rebuild or replacement but the stock volume replacement usually cures the Jeep "tick", other noises, and low pressure. Currently building a 4.0L Renix for my kid's Cherokee and will be adding a Melling HV pump.
If memory serves, the standard volume Melling pump you need is an M-81A. For $60 or $70 and a new oil pan gasket (get the Felpro one piece rubber with steel inserts) is worth a try.
Are you serious? That's some pretty awful pump life IMHO for an engine that is so oft touted as "bulletproof"......
From what I have seen, that has been the average. Sure, there are 4.0L's with 300K with untouched internals, but I've seen pumps fail well before 100K (IIRC one around 60K!).
If the pump has been replaced, as you've guessed - you're on borrowed time.
The 20W50 route is an option. If memory serves, Castrol Syntec 20W50 has a 20 something cSt viscosity at 100*C. You could try that.
Craigslist, online crate engines, and your local club forums would be a good way to find a replacement. The swap could be done in less than a day.
Originally Posted By: Zaedock
If you do in fact, have 0 oil pressure, replace your oil pump. I'm a Jeep guy - have 2.5L and 4.0L rigs, a 4.0L buggy, and work on friends Heeps. In my experience, the average factory pump life is about your mileage. Also, IMO, the factory Jeep upper oiling has never been super. I usually add a high volume pump with either a rebuild or replacement but the stock volume replacement usually cures the Jeep "tick", other noises, and low pressure. Currently building a 4.0L Renix for my kid's Cherokee and will be adding a Melling HV pump.
If memory serves, the standard volume Melling pump you need is an M-81A. For $60 or $70 and a new oil pan gasket (get the Felpro one piece rubber with steel inserts) is worth a try.
Are you serious? That's some pretty awful pump life IMHO for an engine that is so oft touted as "bulletproof"......
From what I have seen, that has been the average. Sure, there are 4.0L's with 300K with untouched internals, but I've seen pumps fail well before 100K (IIRC one around 60K!).
If the pump has been replaced, as you've guessed - you're on borrowed time.
The 20W50 route is an option. If memory serves, Castrol Syntec 20W50 has a 20 something cSt viscosity at 100*C. You could try that.
Craigslist, online crate engines, and your local club forums would be a good way to find a replacement. The swap could be done in less than a day.
Match the viscosity of the oil to the actual clearance in the bearings. In this case, use thicker oil. I'd run 15w40 in cool weather and 20W-50 in hot weather. Because you aren't planning on this for the long run, use the cheapest oil you can find. There is no point buying Lucas or any other additive...buy thicker oil for the same cost as normal viscosity oil.
I don't see the need to jump to a 15w40, many 10w40's will be just as thick at operating temperature but still offer better start up protection and a higher VI. A higher grade should boost your oil pressure though, I concur.
Have you checked your oil sending unit? Your sending unit may be bad (very common) you might not have oil pressure issues at all. It's a cheap, easy fix.
A high mileage 10w40 should be good and thick, Maxlife, Quaker State High Mileage or the new Defy come to mind. Peak 10w40 is thicker than most too, and very affordable if you want to experiment.
Have you checked your oil sending unit? Your sending unit may be bad (very common) you might not have oil pressure issues at all. It's a cheap, easy fix.
A high mileage 10w40 should be good and thick, Maxlife, Quaker State High Mileage or the new Defy come to mind. Peak 10w40 is thicker than most too, and very affordable if you want to experiment.
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