We have a 93 22RE truck that has had a 95 22RE rebuilt motor installed. When at idle, the oil gauge hangs around the middle of the gauge with slight fluctuations. When you accelerate, the gauge drops steadily to the bottom of the gauge. Once you let off of the gas, speed drops, oil pressure will return to the "normal" area, once you get to 45 mph. Anything above 45 mph and the pressure drops.

Anyone got any suggestions, or ideas? Does it sound like the oil pump, the sending unit, or just a really bad mechanic?

 

How many miles are on the motor and pump if you know?

If you're losing pressure instead of holding it, it could be a sign that the oil pump is starting to go. You could try changing your oil to a thicker viscocity and see if your readings improve. If they do...then your pump isn't tight enough to maintain the pressure.

Also you can check if it's a sending unit problem by getting an aftermarket pressure gauge. Craftsman has oil/fuel/compression pressure testing equipment. These are handy for a home mechanic because in addition to fluid pressures you can check cylinder pressure and check on headgasket health.

 

To the best of our knowledge, this motor, since rebuild, has only about 2300 miles on it. Of course, all this assuming that the mechanic is telling us the truth, something we have discovered recently is not one of his better qualities!

The gauge reading fluctuates but oil stays up in the head indicating that pump is at least getting oil that high. Probably the gauge/sending unit would be the best possibilty.

At this point, the engine sounds good, runs well, power o.k., no ticking, etc.

Thanks for your reply.

 

Okay but getting the oil to the head and having good oil pressure are two completely different concerns.

The timing chain will carry oil up to the top of the head whether there's sufficient pressure to prevent motor damage or not. What you need to worry about is is there enough oil pressure to force and maintain that film of oil between the rod and main bearings and the journals. If not you'll have bearing failure and then crank or rod damage or both. This is bad. The cams don't have bearings per se, they use the surface of the journals as their carriers. And trust me dollar wise I'd rather scorch a cam and fix a head then seize a main or rod and replace the whole block.