oil pressure, help please

[equalXlength]

1993 explorer, oil gauge would drop to zero at idle but was fine at any other rpm. I figured the sending unit was bad so ran a mechanical gauge inside the truck. The sending unit was correct at idle there is almost no oil pressure and a 2000 rpm it has 25 pounds of pressure. The motor has 150,000 miles and is pretty quiet and powerful even with low OP. Can someone please tell me what my first step should be to fix my problem, i dont want to drive it like this because i know its going to blow eventually. Should my first move be a motor flush and what should i use. Any help is greatly appreciated. thanks

 

[Big Jim M]

I never advise flushing an engine.. Draining and replacing the oil is one thing but flushing might loosen crap that might lodge in places that wouldn't be the best for the engine.
I might change the oil and filter to a 40W Not a 10w40! For this low cost I might see an incrase at idle.
For sure I wouldn't allow the engine to idle much anymore.
The 25 lbs at 2,000 rpm is within tolorances.. But anything under about 12 lbs at idle would keep me from allowing it to ever idle agin.
Does the engine only have 150K on it for sure and certain?
Big JIm

 

[equalXlength]

i cant be positive but the odometer shows 45000 and im guessing its turned once

 

[Big Jim M]

Well it is 17 years old.. It would have to be an extreemly low use vehicle if 145K is all it has on it. If it was driven an average of 14K a year it would be around 245,000 miles..
At 245K and 17 years one might expect the engine to be well worn and about ready for a rebuild.
Big JIm