Low oil psi at idle when engine is hot

[Knick]

I am a new member to the site and have found it very helpful thanks. I have a 95 6.5 turbo diesel Chevy Dooley automatic 2 wheel drive that I recently purchased. The oil pressure drops slow to 4 or 5 PSI as it warms up. I put new oil pump and main bearings in with no change. The truck seems to smoke a lot White smoke until warm as well please help.

[JeepSJ]

I saw in your other post that you believe the engine to be a '98. It is EXTREMELY important to use the '97-later pump if your engine is a '97 or later. These blocks have holes to spray oil on the bottoms of the pistons to keep them cool, and those bleed a lot of oil. If you use the early pump it will not have enough volume to keep up.

[a5150nut]

Have you tried a mechanical gage instead of electronic? Or try a new sending unit to verify your readings.

[Knick]

I did replace the oil pump with the high-flow later oil pump. I have oil pressure hooked up to Mechanical gauge to verify PSI is correct. I first thought it was the oil pressure sensor and replaced that did not work so went to Mechanical gauge. Thank you so much for your concern and ideas.

[Robyn]

What is the pressure at around 1000 rpm with engine hot ???

As mentioned, these engines have the piston squirters and "bleed" a lot of oil out.

What weight oil are you using ???

15-40 would normally be the oil of choice.

Was the engine worked on previously ???

If it was and one of the squirt nozzles was left out the leak will be huge.

[Knick]

I use Rotella 15W40, and Wix filter I will have to check oil pressure at 1000 RPMs again to be sure what it is but I would say 15 or more. The pressure comes up fast as I push on the pedal . The guy I bought it from said that they put a new Block in at a diesel shop because the previous one had a crack in the block. The truck is blowing out a lot of white smoke when I start it up and does not clear up quick. The truck is a 95 the motor is a 98 or so, work has been done to it I put in new oil pump and main bearings. Bearings did need replacing crank look good and cylinder walls look good so I put it back together thinking it was probably just bearings. I did not think to look for nozzles when I was in there.

[fez3222]

I have 6.5l turbo diesel and when it's warm and at about 1000 rpm it oil preasure on a actual gage is about 10 at idle it's about 5 could a bad bearing b the culprit of loosing oil preasure

[Robyn]

I will assume that the problem came with the rig ???


With that sort of pressure at 1000 RPM there is a leak internally some place.

Even a bad turbo can cause a loss of pressure, but a bad turbo generally will be quite obvious.

Internally it could be a bad bearing, either rod or main or cam, a squirt nozzle left out during a rebuild, a pressure regulator stuck open.

There is also a possibility of a broken main web that has cracked through entirely and allowing a big leak



At this point the only real solution is to do a tear down and ferret out where the oil is going.

Sorry to say, but this is likely not going to be cured from the outside.

I would plan on yanking it out and tearing it all the way down.


Keep us posted