Ive noticed for a while now that when i first start the car the oil pressure seems to read normal. Of course when its cold it reads higher, above the half way point.

My concern though is after i drive the car for a while the oil pressure will drop to like 12-15 at cruising speeds. It also seems to be very delayed on going up on pressure if i down shift and go to speed up. Which worries me at WOT. Also after it warms up when im idling i get maybe 10psi out of it. Now given i didnt drive the car for a long time. But i remember it being higher than that at idle before.
The car does not overheat or anything, but it still worries me, especially at WOT when the oil pressure guage seems to be behind.

What all should i check or replace to chase down the problem?

Thanks.

 

My 94' Z28 does the exact same thing as yours and it only has 68k on it. I noticed the lower oil pressure readings prior to buying the car and did quite a bit of research regarding LT1's and their oil pressure. It seems to be pretty common with these cars for whatever reason and it's still within the factory operating parameters so I shrugged it off. I'm with you in that a little higher pressure would make me feel better.

 

How many miles? Sounds like a tired engine. As bearings loosen up you will lose more oil pressure.

I spun two rod bearings last year, but before I did my idle pressure was still better than yours. So I would be careful, and maybe expect the worst to be coming. Then again it could run like that for years.

That is still in spec with the manual though... I would worry with anything much below 20 at idle. New motor holds 30 at a very warm idle.

 

bout 70k on the engine, about 14k since the heads/cam swap(replaced bearings at that time).

 

Here's some factory spec. info from another thread complaining about the same problem:

"I went to the GM Service Manual to check the specifications. Here is what the book says--Oil pressure minimum: @1000 RPM=6psi.
@2000 RPM=18psi
@ 4000 RPM=24psi At 4000RPM my new gauge showed 25 Lbs or 25psi, all within normal range. "

 

Hmm, i guess i just remember it being higher before hand.. :/ thanks for the help guys.