You're confused on what the gauge measures. It's not level. It indicates oil pressure. It's normal for pressure to drop after the engine warms up because hot oil becomes thinner and seeps out of the engine bearings easier. To drop to low pressure suggests the sending unit is defective, especially if the engine still runs fine with no unusual noise. The place to start is by installing a temporary mechanical oil pressure gauge to see what's really happening. If the pressure really is dropping, the cause should be found and corrected right away to prevent serious damage. If the pressure remains normal, replace the sending unit.
Friday, February 11th, 2011 AT 8:45 PM