1997 Ford Aerostar 6 cyl All Wheel Drive Automatic 212000 miles
Over the last few months, I noticed that the dashboard gauge shows a change in oil pressure. At times, especially after a long drive, the pressure will drop and remain low (and stay constant) until the engine cools down and is restarted. Starting the engine again, the pressure will be back to where it always had been. At all times, however, the gauge shows that the pressure is in the " normal" range, but I am concerned that there may be a incipient problem with the oil pump or pressure regulator. Oil level is fine. We have a long trip planned in the near future.
Have the oil pressure tested with a master gauge, this will screw in where the pressure sender fits and will give a true pressure reading. When you know what the hot idle pressure is, check with the specifications for your car, as it has done a considerable number of miles, I would be considering worn engine bearings, tired pump and pressure relief valve.