Reader Question: Why did oil pressure gauge of my car suddenly move from “normal” to “H”?
The oil level is fine.
Most likely, there is a problem with the Oil Sending Unit, which is what sends the oil pressure data to the dash gauge inside your car. 9 times out of 10, this inexpensive sensor is the problem for erratic or sudden changes in oil pressure complaints.
To be sure of what is going on your mechanic should use a manual screw on gauge to read the oil pressure directly on the engine, but this can sometimes cost as much as just replacing the oil pressure sending unit and guessing that is the problem.