Why is my oil pressure reading so high?!
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Oil pressure reads 70ish psi at idle... And max at 80 and stay there (relative) f any gas is applied. I haven't kept it running quite long enough to find out any other signs of flaw or let it really warm up. I had an old PCM though, that I hooked up and tried and it read 10 to 15 psi under what my current one is reading. Car was not getting gas into 1 cyl with old PCM tho. (bad injector bank) so how can I get an accurate reading? I had 10w30 in (before this issue) and I changed oil with 5w30, 1/4 of a quart of Lucas synthetic stabilizer, and a bottle of zmax. The sending unit seems functional. The gauge is just off, or my pressure is actually scary high. Is there anything else that could go out sensor-wise that would affect this? And my low oil light is on. Not always tho, oil is NOT low tho. Sometimes low coolant will come on as well.
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Verify the pressure with a mechanical gauge first.
If the pressure is correct then the relief valve on your oil pump may be stuck closed. Fixing this would require dropping the pan and having a look-see.
What does not make sense is you say you changed the PCM and your oil pressure was 15psi less? That can't happen because the PCM has nothing to do with the oil pressure gauge. The dash drives the sensor, not the PCM.
If the pressure is correct then the relief valve on your oil pump may be stuck closed. Fixing this would require dropping the pan and having a look-see.
What does not make sense is you say you changed the PCM and your oil pressure was 15psi less? That can't happen because the PCM has nothing to do with the oil pressure gauge. The dash drives the sensor, not the PCM.
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Is there such a thing as oil pressure being too high? I've always thought the more the better. I know I've seen increases in oil pressures when thicker oil is put in the motor. Maybe the additives you put in the motor thickened it up quite a bit. My escalade with a stock 6.0l gets 80psi when driving, 20w-50 oil.
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Oil pressure is always higher on cold start because the oil is cold (simple). High oil pressure is not a good thing. The pump has to work harder which costs horsepower, many oil filters aren't designed for sustained high pressures which can result in them exploding. Also with the relief valve fully open most of the oil ends up back in the pan reducing cold-start oiling.
The right amount is far more important than having too much.
The right amount is far more important than having too much.
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And yes there is such thing as too much oil pressure. All oil pressure is really is the resistance that the oil is experiencing to movement. The higher the pressure, the more resistance and heat that is put in to the oil. Also, the harder the oil pump drive is stressed, the harder the camshaft is stressed and so on and so forth.
Just like at a certain point adding boost doesn't create anymore horsepower but only more heat. More oil pressure is not always better. You only need enough oil pressure to get the oil where it needs to go in the engine. Beyond that you are just spending money to change your oil more often since the oil is breaking down much quicker.
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I usually run the thicker oil in the winter months, when I do a summer oil change I will run a lighter weight. I prefer the heavier oils just for the coating factor, just a personal preference. With this weight, the lowest I've seen it go is 60psi in my kid-caddi. I run the 20w-50 (synthetic racing oil) in my race cars also, no matter what time of year. Sounds like we have the same body style (I've got the ESV model to hold all my kids), pearl white?
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Verify the pressure with a mechanical gauge first.
If the pressure is correct then the relief valve on your oil pump may be stuck closed. Fixing this would require dropping the pan and having a look-see.
What does not make sense is you say you changed the PCM and your oil pressure was 15psi less? That can't happen because the PCM has nothing to do with the oil pressure gauge. The dash drives the sensor, not the PCM.
If the pressure is correct then the relief valve on your oil pump may be stuck closed. Fixing this would require dropping the pan and having a look-see.
What does not make sense is you say you changed the PCM and your oil pressure was 15psi less? That can't happen because the PCM has nothing to do with the oil pressure gauge. The dash drives the sensor, not the PCM.
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Yep...OP keep puttin it in there. Your oil pressure will be lower in no time!
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Maybe you should read up a bit more on those additives. There not just joe blow magic juice. There is science behind it. Also, I use casterol GTX. I dont think the sending unit is bad... I though it went out but it was actually the wire pulled out of the plug. So I found a perfect match spare female connector and installed it with an extra piece of wire, and sodered it in. Due to the old segment being very tightly pulled to reach. Gig the gauge of wire I spliced in was larger. Would that throw the gauge off 15-20 psi reading?
Where can I hook up a mechanical gauge to view it?
Where can I hook up a mechanical gauge to view it?
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Oil sensor is only connected to the dash at least in my car the gauge was somewhat accurate.
More is not better, a very rough approximation for a sbc is about 10psi per 1000 rpms. Although racing motors run as little pressure as needed. So they might spin to 8-9000 and only take 55-70 psi to do it, they may also run thinner oils.
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Last edited by Numba20; 05-07-2013 at 10:26 PM.