I have an Auto meter manual oil pressure gauge along with the stock one on my car. My engine was recently rebuilt 5k ago. I’m using 10-30 oil with a purolator oil filter, at start up both gauges read 45-50 psi but when the car gets to 190 degrees at idle I get 18-10 psi on the manual gauge and 20 on the stock gauge @ 750 rpm. What do you think is wrong? Maybe the oil filter

 

hrmmmm

 

I just rebuilt the engine I hope it’s not something serious

 

Sounds like fairly normal LT1 oil pressure with the stock pump...did you upgrade your pump?

If it makes you feel better you are cleanly within GM's service range for oil pressure (meaning that they wouldn't pay a dealer to spend any time investigating it under warranty).

GM says that 7.5psi is min at 750 RPM's. - JM.

 

sounds normal to me

 

if you have a high flow pump in the stock pan. that could be your problem.

I just recently fixed mine with a baffle and a windage tray along with a stock M55 pump with a 70 pound spring. Solved my problem. Also there could be a chance u shattered ur oil pump drive assembly. Change ur oil and let us know if there are any metal shavings/teeth in the filter or oil.

A high flow/volume pump in a stock LT1 pan has been said to suck the pan dry of oil and which will make u loose pressure. Happen to me too.

If none of these things include you, then i would hate to say your engine is on its way out.

when cold my pressure goes up to around 70-75. Warm it ides from 20-25 and cruising warm it ranges drom 45-35.
It usually runs lower when my car hits in OD and rruns just a tad under the middle mark (which is 40psi)

 

I used a stock oil pump.

 

theres nothing wrong with that. I have a stock M55 pump in mine along with a different pressure spring.

 

At idle?....must be a heck-of-a pump.


Originally Posted by Stan1
I used a stock oil pump.

There's nothing wrong with a stock pump, I think that we have enough info now to say that you oil pressure is NORMAL for an LT1.

If you want you could start running a 10w-40, or 5w-40, or 0w-40, any of these will likely bump your hot oil pressure up a bit, and many say that they provide better hot protection in an LT1 application...I however still live in the dark ages and run 10w-30 dino oil. - JM.