dropped oil pan and put in upper and lower oil seals. fixed leak. but now, when i first start, plenty of oil pressure, but after driving for 20 minutes, none to speak of. also when i first start up, you can hear the mains. any thing i can do or open for suggestions. thanks

 

Does it still have oil in it? You didn't blow it all out the back going down the road, did you?

 

God, I hate this kind of story....do all the work to fix something so it is RIGHT then some other problem dumps all your work and makes it worse. I hate it when it happens to me and hate it almost as much when it happens to somebody else.

 

no, plenty of oil. have drained 10-40 and put in 20-50.

 

If your gonna open up the engine then do it all.

When you replace the bad part the next weakest link in the chain shows itself.

 

Do you have a faulty O/P sending unit? Or maybe a pizzled pump and/or pickup? - Disconnect and remove sender, install O/P Line and Gauge tool (my '99 Jeep Chero XJ service manual indicates part number C-3292 or equivalent), start engine and record pressure - maybe even drive again as described and compare to previously observed results - O/P at idle (600rpm) should be 13psi, at 1600rpm and higher O/P should be 37-75psi, O/P relief should occur at 75 psi. If readings/values are insufficient, then it sounds like an issue with the oil pump and/or pickup. Not sure, but I think there's a way to spin the oil pump without running the engine in-order to help verify oil pickup/pressure (oil pump slot on side of engine). Otherwise, get ready to re-drop the pan to inspect the innards...