High oil pressure
#1
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Location: Grayslake, IL
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High oil pressure
I have high oil pressure, I hooked up a mech gauge, and when cold at idle, i have like 70 psi, when warm (in park) i have 60 psi at idle, and after driving, at idle, in drive, at a stoplight or whatever, i have minimum of 40psi, now I only confirmed the 70psi and 60psi with the mech gauge, and since that was near the reading I was getting on my dash I believe that to be accurate, by the way I just found this site and am extatic that there are forums with a lot of people here to help, so, what do you all think, I swapped the filter and rechanged the oil, nothing, my question is, is this dangerous? Is it ok to drive every day?? I dont want to risk pushing oil into somewhere it doesnt need to be. What could it be??
#2
Senior Member
True Car Nut
That is normal. I'm pretty much 90% sure.
That means your intake gaskets have NEVER failed, your engine is basically brand new I think with those numbers. That is...as far as the bearings being on their way out. Your year of bonneville, well the engines usually last 300,000+ if something else does not go wrong before that miliage.
That means your intake gaskets have NEVER failed, your engine is basically brand new I think with those numbers. That is...as far as the bearings being on their way out. Your year of bonneville, well the engines usually last 300,000+ if something else does not go wrong before that miliage.
#3
definitely. that engine is fine. at that mileage, damn near perfect...if your gauge is out of whack, its possible that it is a bad sender...but then again it could just be that you have good oil pressure, which i definitely don't doubt....
That LN3 has many more miles to go. Don't worry.
That LN3 has many more miles to go. Don't worry.
#4
DINOSAURUS BOOSTUS
Expert Gearhead
As a gearhead on this forum I would caution you against taking the advice of either Hans or WJCollier.
Another member had a similar problem and it ended up blowing the lower end of the motor.
While I'm not 100% sure on the cause, I suspect that the oil pressure relief may be stuck. This is a spring and piston type piece of metal that are located behind the oil filter adapter plate. This is easily gotten to by removing the passenger tire and splash shields.
My thoughts are that you don't run the car if not necessary until you can get a new gasket (dealer only, cheap though) and remove the oil filter and adapter to check for issues or binding.
Another member had a similar problem and it ended up blowing the lower end of the motor.
While I'm not 100% sure on the cause, I suspect that the oil pressure relief may be stuck. This is a spring and piston type piece of metal that are located behind the oil filter adapter plate. This is easily gotten to by removing the passenger tire and splash shields.
My thoughts are that you don't run the car if not necessary until you can get a new gasket (dealer only, cheap though) and remove the oil filter and adapter to check for issues or binding.
#5
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I work at a chevy dealership so that shouldnt be a problem, but is there any special tool needed to remove/install this spring and pin? I will do it today after work if I can get a gasket for the oil filter housing today, but if its as easy as it sounds, then I can do it. Will the old filter have to come off or can I get all of that off with the filter on? What should I look for, a pin that doesnt pop out when the oil filter housing is removed? What do you do if that were to occur, replace or clean the pin/spring? I just bought another filter and put it on yesterday, any money I can save would be a plus.
#6
DINOSAURUS BOOSTUS
Expert Gearhead
No special tools, the bolts IIRC are 13mm and there are 4 of them. The oil pressure sender will come off first (pliers). As for anything flying across the bay, it shouldn't...however remove the adapter slowly, knowing there'* a spring loaded piece behind it. Unscrew the filter and sit it on the bench.
I would remove that piece and check it. Look for any binding in it'* movement etc. Maybe sludge? If so..clean appropriately. Never having seen the problem first hand..it'* tough to speculate what you might find.
I know that for the newer motors (series 2) Intense Racing sells a kit with spring/piston piece that you can replace with to increase pressure. That'* about my knowledge on the system though.
There is a post that I started in the Gearhead area, spiking this thread out as one for the others to add their knowledge. There should be more responses soon... (they sleep late...what can I say)
I would remove that piece and check it. Look for any binding in it'* movement etc. Maybe sludge? If so..clean appropriately. Never having seen the problem first hand..it'* tough to speculate what you might find.
I know that for the newer motors (series 2) Intense Racing sells a kit with spring/piston piece that you can replace with to increase pressure. That'* about my knowledge on the system though.
There is a post that I started in the Gearhead area, spiking this thread out as one for the others to add their knowledge. There should be more responses soon... (they sleep late...what can I say)
#7
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On my 91 LN3 3800, I usually cold start at 70psi, Hot idle is usually 40 Psi, and anything above dead idle is 55-60 Psi...
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#9
Senior Member
True Car Nut
What Boosty is talking about is the oil pressure relief valve. It is located in the adapter piece as he described and consists of a spring and a piston in a bore that connects to a bypass passage to the pan. The spring pressure is set for 60 pounds IIRC. (I'll check my '92 FSM.) Usually, over time, the spring weakens and allows the piston to bypass pressure below 60 psi; sometimes the piston sticks in the bore, and the pressure rises well above 60. It is not unusual when the engine and oil are cold, for the oil pressure to exceed the relief setting, e.g., your 70 psi reading. Your pressure readings are what I might expect for a new engine, but your engine is not new. If you know the history of the car, and the pressure has always been like this, you are in great shape. But, if the pressure is higher now than it has been in the past with all other factors equal, then the increased pressure could be caused by a blocked oil passage. Factors that affect oil pressure include: viscosity of motor oil, engine temperature, and ambient temperature.
(goes to find '92 FSM........OK, pressure should be 60 psi at 1850 rpm with 10W30 oil at normal operating temperature (probably 195F))
(goes to find '92 FSM........OK, pressure should be 60 psi at 1850 rpm with 10W30 oil at normal operating temperature (probably 195F))