Engine Oil Pressure Questions
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 9,910
Likes: 1,858
From: Hot Springs AR
Engine Oil Pressure Questions
I posted the following question over on Z06Vette.com, but thought y'all might be able to help me out as well:
I've got a friend with a '03 Z06 that's developed a problem with the oil pressure indications. Idle oil pressure with cold oil used to be in the high 30s, now it's down around 26.
When he was on the track this last weekend he got a "Low Oil Pressure" alarm, and the oil pressure was below 10 psi indicated. He immediately pulled off, coasted in, and shut down. Oil pressure never went to zero, and recovered back to 26 psi cold.
We haven't heard any audible signs of distress out of the engine, and looking at some oil doesn't show any sparkly stuff, so I'm hoping the engine isn't hurt.
What could cause this? I've got three suspects:
1. Oil pressure regulator spring has cracked or broken
2. Oil pump has suffered partial failure
3. Oil pressure sensor has failed
Or, is there something else that I'm missing?
TIA for any help, and have a good one,
Mike
When he was on the track this last weekend he got a "Low Oil Pressure" alarm, and the oil pressure was below 10 psi indicated. He immediately pulled off, coasted in, and shut down. Oil pressure never went to zero, and recovered back to 26 psi cold.
We haven't heard any audible signs of distress out of the engine, and looking at some oil doesn't show any sparkly stuff, so I'm hoping the engine isn't hurt.
What could cause this? I've got three suspects:
1. Oil pressure regulator spring has cracked or broken
2. Oil pump has suffered partial failure
3. Oil pressure sensor has failed
Or, is there something else that I'm missing?
TIA for any help, and have a good one,
Mike
Burning Brakes
Joined: Feb 2002
Posts: 871
Likes: 1
From: Union KY
I'd bet on the pressure relief spring.
Reasons: The low pressure noted and the fact that it dropped to near zero on the track and then came back to 26 after the engine cooled. Oil pressure is related to oil viscosity and 400 F. oil is pretty thin. After it cooled to say 200, it would allow the engine to generate a higher pressure.
In turn, the weak pressure relief valve spring would give you low pressure readings all of the time. Having said all this, it could be a bad pump, or sending unit. I'd try the sending unit first, then the relief valve.
Good luck. Let us know what you find.
Cire
Reasons: The low pressure noted and the fact that it dropped to near zero on the track and then came back to 26 after the engine cooled. Oil pressure is related to oil viscosity and 400 F. oil is pretty thin. After it cooled to say 200, it would allow the engine to generate a higher pressure.
In turn, the weak pressure relief valve spring would give you low pressure readings all of the time. Having said all this, it could be a bad pump, or sending unit. I'd try the sending unit first, then the relief valve.
Good luck. Let us know what you find.
Cire
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 9,910
Likes: 1,858
From: Hot Springs AR
Cire,
It was a clogged oil filter. Amazing how the brain just jumps to what it wants to think the answer is, rather than looking at all the possibilities. My friend had been doing some research on the Z06 forum and that one popped up.
Changed out the filter and the idle pressure came right back up to 37 psi. Tonight we'll cut the filter open and see if there's any ugliness in there.
Have a good one,
Mike
It was a clogged oil filter. Amazing how the brain just jumps to what it wants to think the answer is, rather than looking at all the possibilities. My friend had been doing some research on the Z06 forum and that one popped up.
Changed out the filter and the idle pressure came right back up to 37 psi. Tonight we'll cut the filter open and see if there's any ugliness in there.
Have a good one,
Mike
