1999 Dodge Durango Engine oil pressure drops at constant

TBONE99

MEMBER
1999 DODGE DURANGO
V8
4WD
AUTOMATIC
221,000 MILES

I am baffled with this oil problem.
I have a mechanical oil gage installed besides the electric from dodge - start engine cold 60psig - hot operation 45-50psig under load.
driving on the highway the oil pressure will start to drop slowly from the 45psig down to 20 psig. It is affected by increase in engine RPM (climbing hill - transmission drops down a gear) the oil pressure will decrease and stay at the lower level. I have verified my oil level as proper and less than 1000 miles since last oil change.
What baffles me is that if I stop the car, turn it off and restart the oil pressure will return to 45-50psig underload / 20-25psig at idle and response properly to accelerator. As I drive on the highway again it will slowly decrease in pressure again.
This has been occurring after several oilchanges and engine flushes - initially thought I had a bad oil filer.

Any thought would be appreciated.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,640 POSTS

Hi:
How do you have both gauges hooked up at the same time? Or do you have one at a time?

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Tuesday, March 10th, 2009 AT 4:55 PM

TBONE99

MEMBER
2 POSTS

I piped in a T connection at the engine. The electric transducer is off the verticle portion of the T and the mech gage is off the horizontal connection - total mech gage which I mounted on dashboard. Ran the tygon tubing through the fire wall, used a spare penetration I found.