Oil pressure at idle going up
09-20-2011, 11:09 PM
#1
Oil pressure at idle going up So I start my car and the oil pressure builds up to around 40, then i drive it and it goes down. not all the way, but little by little. Then when i pull back in to my garage it starts getting normal again. I think the problem is a bad valve cover bolt, but i have 98 style valve covers and they look like they are built in to the valve cover itself. Is there any kind of quick and easy fix so i can still drive the car normally?
09-22-2011, 12:23 AM
#3
I would check in order:
1. Oil in engine. Seems simple, but there may be a large leak.
2. Oil pressure sending unit. If they are cracked or in any way damaged they will cause odd oil pressure readings. I just went through this with my 95 DD.
3. Mechanical gauge to verify oil pressure readings.
From there you'll be able to tell if you have an actual problem with oil pressure or a faulty reading.
1. Oil in engine. Seems simple, but there may be a large leak.
2. Oil pressure sending unit. If they are cracked or in any way damaged they will cause odd oil pressure readings. I just went through this with my 95 DD.
3. Mechanical gauge to verify oil pressure readings.
From there you'll be able to tell if you have an actual problem with oil pressure or a faulty reading.
09-22-2011, 01:39 AM
#4
im pretty sure the guage is working, because when the oil pressure gets low, it makes a ticking noise that gets louder as you go and the pressure gets lower. Then i let it sit in my garage and idle a little, then the oil pressure went back to around 40. I suspect that it is losing pressure through the valve cover where the bolt would be
09-22-2011, 01:52 AM
#5
09-22-2011, 02:25 AM
#6
not saying that the hole itself is the cause of the pressure leak, i guess what i am asking is if the seal of the valve cover gasket would be weak enough at that particular point (bolt hole) that it would cause a pressure leak. Mostly because the bolt isnt fastening down that point in the seal.
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09-22-2011, 12:22 PM
#8
It's also possible your oil pump is getting weak and can't pump hot oil very well above an idle. Like said, if it's not the gauge, then it has to be caused by a real physical problem. Also as said, there it no oil pressure inside the valve covers. You could remove both valve covers and still have the same oil pressure.
09-22-2011, 03:34 PM
#9
^ Oil pump is a possibility, but... I just went through this exact same thing with my 95. I would fire the car up, get great oil pressure, drive for a while, and then it would plummet. Recently, the oil pressure would jump around even when warm and I was losing a lot of oil. It ended up simply being my oil pressure sending unit was cracked, causing bad oil pressure readings, and leaking oil. I replaced it and my car is instantly better.
I'm willing to bet that if you pulled off the LS6 intake manifold you have for sale in your sig and exchanged it with something else that you might have cracked or broken the sending unit. They'll snap like a twig under any pressure.
I would be safe and start easy. Confirm that you have oil in the engine and the gauge works. Sometimes it is the simple things that will drive you insane. Not to mention both of those tasks can be done extremely quickly.
I'm willing to bet that if you pulled off the LS6 intake manifold you have for sale in your sig and exchanged it with something else that you might have cracked or broken the sending unit. They'll snap like a twig under any pressure.
I would be safe and start easy. Confirm that you have oil in the engine and the gauge works. Sometimes it is the simple things that will drive you insane. Not to mention both of those tasks can be done extremely quickly.
09-22-2011, 03:58 PM
#10
I have my old LS1 intake back on. Have had it on for a while now. I need to update my sig. Sorry bout that. I will go and rent or buy an oil pressure guage now and post up what happens. I have always been EXTREMELY careful when removing the intake that when i take it out the hose doesnt get caught on the sending unit, but i have been known to make mistakes... from time to time... thanks everyone. stay tuned!
09-22-2011, 05:00 PM
#11
Autozone and Kragen dont have the guage. Shitty, but i do know that when the oil pressure drops i start to hear a ticking noise, which leads me to believe there actually is no oil pressure, it isnt just the guage acting up, but im going to take off the sending unit now and check it for cracks.
09-22-2011, 05:05 PM
#12
Could be that either the oil pump pickup screen is stopped up or the O-ring where the pickup tube goes into the pump is leaking, allowing the pump to suck air instead of oil.
09-22-2011, 09:54 PM
#14
Well, that stinks on the lack of an oil gauge. I'd still check the sending unit to make sure that it isn't cracked. The only reason I keep saying this is I just went through the exact same issue. My car would smoke and show little or no oil pressure when hot. With 197k on the clock you might be at the end of the life of an oil pump though. The O rings don't tend to go out, but rather get messed up on installation and then pinched.
