Questions and Answers

S-10 High Oil Pressure Q. Hi, I have a question concerning the oil pressure of my vehicle. My truck is a 1985 Chevrolet S-10 4X4 with a 2.8 liter 2 bbl. It has air conditioning and auto transmission.

Anyways, the oil pressure gauge reads between 70 and 80 psi at all times - hot or cold, idle or highway driving. The manual states that normal oil pressure should be between 20 and 40 psi. The thought of a bad sending unit comes to mind but I doubt that is the problem. The needle of the gauge is fairly steady so I know the connection is okay. However, the engine was installed by the guy who owned before me in 1995 at GM Goodwrench. As far as I know, this new engine has the same specs as the original one. There's only 38,000 miles on it.

Is too-high oil pressure bad? Maybe you can help.

Thanks

A. There are three distinct possibilities for this problem. A bad sending unit or dash gauge, a stuck pressure regulator valve or the wrong weight motor oil.

Assuming the oil is correct the only way to determine if the pressure regulator valve is stuck is to do a mechanical oil pressure test. The OPS unit is removed and a mechanical oil pressure gauge is installed and if it indicates the 70 to 80 pounds of pressure, you have a stuck valve. If this is the case the oil pump will have to come apart to replace or repair it.

If the gauge reads normal oil pressure, then the problem is in the OPS or the dash gauge. To check this, remove the mechanical gauge and install a new OPS. If the dash gauge shows normal pressure, then you have fixed the problem. If it still reads high, you have a bad dash gauge.

Additional Information provided courtesy of ALLDATA