Oil pressure

[Dlowe]

At start up I have 55lbs.....once it's at operating temp it drops to almost zero? I installed a mechanical gauge to be sure. Will a set of main bearing correct this problem? I'm new a this, I see I'm in the wrong forum.

 

[Dlowe]

I was really hoping to get some advise on this issue.

 

[CJ]

There could be many things causing this problem. Worn main, rod or cam bearings. A worn lifter bore. Even a bad pump or filter.

What have you tried to fix this? What have you checked? What weight oil are you running? Do you have any blowby?

Any info you can provide helps.

 

[Dlowe]

I installed the mechanical oil gauge to confirm, flushed the system with a product napa sells. New oil and filter with 10w30. It has no blow by. Once the engine is warm and the pressure has dropped off the chart I get a lifter noise that comes and goes. It had sat for almost ten years in a field. Thanks for your help.

 

[Dlowe]

I installed the mechanical oil gauge to confirm, flushed the system with a product napa sells. New oil and filter with 10w30. It has no blow by. Once the engine is warm and the pressure has dropped off the chart I get a lifter noise that comes and goes. It had sat for almost ten years in a field. Thanks for your help.

 

[harborman]

I installed the mechanical oil gauge to confirm, flushed the system with a product napa sells. New oil and filter with 10w30. It has no blow by. Once the engine is warm and the pressure has dropped off the chart I get a lifter noise that comes and goes. It had sat for almost ten years in a field. Thanks for your help.

I have the same thing almost. The AMC 258 i6 / 4.2l is notorious for low pressure. Sitting for 10 years in a field is not good, seals dry out, etc. Does it leak any oil? Try a heavier oil and see what happens.

 

[Dlowe]

The fuel pump and valve cover leaked a little. I replaced them and otherwise seems tight. My dad suggested main bearings. I'll try heavier oil. I'm considering main bearings and a high volume oil pump if available. Do you have lifter noise that comes and goes after the pressure has dropped off? Thanks for responding.

 

[harborman]

The fuel pump and valve cover leaked a little. I replaced them and otherwise seems tight. My dad suggested main bearings. I'll try heavier oil. I'm considering main bearings and a high volume oil pump if available. Do you have lifter noise that comes and goes after the pressure has dropped off? Thanks for responding.

No lifter noise on mine. I did have a valve job, new cam and lifters installed some years ago. Now that I am back tinkering with it, I may just pull the block and have a short block put in. 140K on motor.

 

[7D8CJ]

Definately drop the oil pan and check pickup for sludge. You should also plastic guage the mains for oil clearance.