I went racing at Fernley, NV this weekend. My Saturday morning sessions were great and the car ran perfect. Then about mid-day I noticed a sudden change. When I started my engine I got an error message saying "Low Oil Pressure". Checking gages, it showed 0 pressure for about 5 seconds before it slowly came up to normal. After that, everything was normal and my engine ran fine, however while idling oil pressure would be low at like 9 lbs instead of the normal 30. I also noticed a new sound when starting the engine that I never had before just after engine start and before oil pressure would register. It didn't sound like lifter noise but rather a rotating-like grinding like noise which immediately would disappear as soon as oil pressure came up. Doesn't sound like the problematic sensor issue and makes me wonder if there is a oil pickup problem, an oil pump priming problem or an imminent oil pump failure.

Some Info on my car:

- Stock w/MN6
- Racing sessions ran 20 min on and 40 min off throughout the day.
- Used standard Moble 1 5w-30 synthetic
- Oil level was correct and wasn't burning much
- Idled the car after each session with hood open to cool down to normal temp before shut down
- Oil pressure while racing always above 50lbs
- Oil temp ~238 deg
- Engine temp normally at 196 and up to 226 during sessions
- Both fans running

Any ideas would be greatly appreciated. This does worry me.
Thanks.
John

 

Sounds liek the same problem i have had on my 98 wich u have the same year. the oil pump went to hell. Somhow it got chewed up and lucky i caught it before it caused damage. If i were you i would pull the pump and get a ported Z06 one and its a good time to change camshaft since u are 95% torn down.. Also check your timing chain...

 

ive heard of casting flaws in the oil pan being sucked up into the oil pump and messing the gears up...sounds like you need a new oil pump

 

Your Oil pressure relief valve is sticking. Mine had red locktite on it from the factory. When it's stuck open on start up you aren't bilding OP.

this is probably also causing your oil pickup tube to get clogged causing the low OP. It's getting clogged because not enough oil is getting to your #8 cylinder and is coking the oil as it goes by.

Pull your oil pump, replace it, and make sure you clean the oil pickup tube.

Your living on borrowed time if you don't.

IMHO but I've been there done that and got the T on this one.

 

Do you have to pull the engine to change the oil pump?

 

No

might as well do a cam if you dont already have one while you have it apart though

 

Go to LS1Howto.com and check out his cam change instructions, it will lead you to the oil pump change. Great photo's of the process and you will understand it a lot better.

Good luck.