What might cause LOW oil pressure on GMC k2500 Sierra?

[josh]

I have a 1992, 90k miles GMC Sierra K2500 5.7L V8 engine.
When it is warm outside, the oil pressure drops to above red line, if i idle it is in red line and is around 100 rpms.
When it is cold outside, the oil pressure is about 3/8 the way up the meter, if i idle it is 4.5/16 the way up the meter. RPMS stay relatively the same as when it is warm outside.
I know this is a problem, but i want to know, is it: bearings, oil type/leak, maybe a bad meter, or other? Also if you give an answer, please list an approximate price in repair. short on pocket cash.


knew i shouldn't have bought the damn thing.

 

[Molson02536]

I have a 1992, 90k miles GMC Sierra K2500 5.7L V8 engine.
When it is warm outside, the oil pressure drops to above red line, if i idle it is in red line and is around 100 rpms.
When it is cold outside, the oil pressure is about 3/8 the way up the meter, if i idle it is 4.5/16 the way up the meter. RPMS stay relatively the same as when it is warm outside.
I know this is a problem, but i want to know, is it: bearings, oil type/leak, maybe a bad meter, or other? Also if you give an answer, please list an approximate price in repair. short on pocket cash.


knew i shouldn't have bought the damn thing.

Start with the simple and replace the oil pressure sensor, it's located on the passenger side behind the distributor. If there is no knocking or ticking noise then the oil pressure in your engine is fine and the pressure sensor has gone bad and will need to be replaced.

If you like which is a good thing is to add a bottle of Marvel Mystery Oil to your engine oil and running it for 500 miles before your replace the oil pressure switch and service the engine. This will clean out the oil passage ways and free up oil journals bring the oil pressure back to where is should be if there are no worn parts like the main bearings.

Keep me posted and good luck.