subliminal

iTrader: (1)

Yesterday I took my car out to just go down the road a few blocks and as I was sitting in the drive through of Mcdonalds I noticed my oil pressure taking a drive.
At first it went to 15 and the warmer the car got the lower the Oil pressure became until it went down to just below Zero.

I drove the car home trying to keep the RPM's as low as possible. And I went and tried working on it yesterday to try to figure it out. I checked the coolant and made sure it didnt have any Oil in it and that the car wasnt low on oil or anything. And the engine isnt making any funny noises or smoking at all.

If I start the car when it is cold the pressure will be around 20 but as the engine gets warmer the pressure drops back down to just a tad above zero. If anyone can help me out with this Id greatly appreciate it.

84 z28

When the car is cold the oil is thick.By time the car is at it running temp the oil is hot and thinner. You could go with a thicker oil like a 20-50 and it would the oil pressure up a bit. Has your car been sitting in storeage or is it a dialy driver ?? Depending on your cars mileage it could be a worn oil pump or maybe the pickup on it is cloged . Car should have 10psi for every 1000rpm I believe FYI.

sofakingdom

iTrader: (1)

It's almost certainly not the oil pressure itself, if the motor isn't making a bunch of clattering and knocking noises; rather, it's the gauge system.

Change the oil pressure sending unit... the thing that tells the gauge what the pressure is. They go bad ALL THE TIME.

bilms01

Worn bearings, cam, main and rods can cause that also.

I would put a direct reading guage in if you haven't already just to make sure the pressure is actually going that low. IIRC 3 or 4 PSI if where the OPsU will open and shut off the fuel pump

sofakingdom

iTrader: (1)

If the engine isn't making funny noises, it's almost certainly not a bearing issue. Those have a way of letting you know in no uncertain terms when they're ready to retire.

Putting a direct reading gauge is about 3 times the PITA that changing the stock sending unit is, and costs extra $$$; and all it will tell you, is that you need to change the sending unit because your stock gauge reads wrong. Then you gotta change the sending unit anyway.

Proceed directly to the quickest, cheapest, and most likely solution to the gauge indication problem. Just change the sending unit. If that doesn't make it read right, THEN worry about those other things.