I have a 2000 4.0 Wrangler and lose oil pressue at idle after the engine heats up. I have following symptoms but can not find a solution
1) Losing 4 qts of coolant every 800 miles. There is no sign of where it is going. Not on the ground, under the hood, through the exhaust or in the oil.
2) It appears that the oil is getting very hot. The grip on the oil filter is turning to dust at oil change time and the oil gets dark very fast. There is a hint of a burnt smell in the oil also.
3) Engine temperature is ok, never overheats.
4) Oil pressure starts at 40 psi when engine is cold and drops to zero at idle when engine is hot. I have removed the oil cap and can see a good amount of oil circulating over the lifters.
5) Oil pressure sending unit has been replaced with OE part.
My only theory is that the coolant is not circulating through the entire engine, only a portion of the motor and this is causing the oil to over heat and get very thin.
I know that I have seen this issue posted several times, but have not seen a resolution other then replace the motor.