Hi all, I have a 99 Ram 1500, 5.2l and my question is what would cause the engine oil to drain back into the pan overnite? I replaced the oil pump but it still does this. I have a napa gold filter on also w/ anti back flow. It seems as the pump is losing its prime. I'm also replacing the plenum gaskets and plate (oil in pan, using oil, shift troubles, loss of power) so I hope that takes care of that. Could the plenum gasket cause the loss of pump prime? Any help I can get would be great. I've done alot of searching but haven't found much on this.

Thank You
Dan

 

It will always take a few seconds for oil pressure to build when you first start the truck. Pressure bleeds off in a multitude of ways, most of which are part of the design of the system. Keep in mind, it is only because of restriction that you have pressure in any event, and when the supply turns off, pressure bleeds to zero. When you restart the engine, the oil has to refill the volume vacated from just sitting. Normal. Should take more than a few seconds for oil pressure to come back up though.

This is why some companies developed 'pre-lubers' for engines. All it is, is an accumulator, that holds pressure when the engine is off, and when you turn the key to on, it opens a valve that instantly builds oil pressure. (80% of engine wear occurs at startup........) An interesting concept...... but, it isn't bearings and such that are the usual cause of engine death. Generally, its rings, or valves, that go first, and oil pressure has little or nothing to do with that.

 

 

one thing to keep in mind for these trucks, is the oil pressure gauge is not an actual pressure gauge, it just tells you you have some pressure, when it falls below a cirtian pressure, it drops the gauge and sets the check gauges light, in the reverse order the engine has to build a cirtian amount pressure before the gauge will read anything, it tends to make things a bit scary at times, but its just a dummie gauge, for piece of mind you may try a temperary or permanent mechinacal pressure gauge

 

How do you know it drains back????????

 

Well when at first start-up the gauge shows no pressure for about10 seconds, plus before the oil hits the pump you can here a fast clacking sound and as soon it goes away the pressure comes up. It takes alot longer when it's very cold. You can actually here the change in the motor running when the clacking is gone and the press comes up.

Thanks again
Dan

 

lighter oil will help with that a lot

 

I'm having a similar issue, however, when my truck is sitting at idle it will vary from 39-43...but when I am giving it gas at highway speeds its normal. Oil has been checked and i'm good there. It wasn't doing this before....

So, in turn....is it an oil pump issue or something worse like I am suspecting (plenum)

 

when oil warms up, it thins out, so its going to lose a bit of pressure....39-43 is perfectly normal.


and 10 second for it to flow through? my guage goes right past 40 everytime i start it up within a second regardless of weather. Do you have a sludge build up?

 

Not sure but I'll find out this coming week (plenum).