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Join Date: Oct 2004
Location: San Jose CA
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Re: What should oil pressure be on factory gauge?
It is normal that oil pressure will drop a little as the engine collects more miles due to bearing clearances increasing. As someone else mentioned, and I believe it to be solid information, you need to see at least 10 psi per 1000 rpm. So at hot idle, 10-20 psi is fine. Driving hot, 30-60 is fine. Cold will usually max out the pressure and put it into bypass.
Here's what I would do. I'd use factory recommended weights (10-30 or 5-30). Note the pressures under different driving conditions such as outdoor temp and engine temp. If the pressure seems to stay consistent with these different conditions, then that is a good sign. If you start to see the pressure significantly drop out of your engine's range or out of the 10 psi/1000 rpm range, then you may have some bearings that are starting to fail or wear out or maybe a bad pump. If you start to get some rod knock, then it is time for a rebuild.
A note about oil pressure and oil weights. Some guys will put in heavy weight oils to boost the oil pressure. This may boost the oil pressure and look reassuring on the gauge but it may well reduce oil flow. Oil performs 2 main jobs, it lubricates and it also COOLS. If you reduce the flow by putting in heavy weight oil, the flow will drop and the cooling capacity of the oil will also drop. Not good. Again, as long as you are getting 10 psi/1000 rpm, don't worry about it and stick with the factory recommended oil.
2001 S10 2.2 5sp ext cab
Don't hit and run...let us know how you fixed it!