OK, I've never seen this before. On a '92 4.0 on 5W-30 GTX synthetic and 189,000 miles, that has always carried 40-60 psi of pressure at start and 30-50 psi in normal driving conditions, it will now start cold (below 40 degrees F)with 40-50 psi at idle and as rpms increase the pressure will drop to 20-30 psi. As rpm drops pressure will build back to 40-45 psi. This behavior continues untill several thermostat cycles are observed and then stabilize around 40-45 psi. I need input.
-is this a:
-clogged filter/pickup screen
-failed (partially open) relief valve
-excessive viscosity at low temperature causing cavitation
-failed sending unit (has been replaced)
-ideas?
Jeep4X4
-is this a:
-clogged filter/pickup screen
-failed (partially open) relief valve
-excessive viscosity at low temperature causing cavitation
-failed sending unit (has been replaced)
-ideas?
Jeep4X4