I have a 1999 1500 Sport with a 5.2 that loses oil pressure to where the lifters rattle. Changed oil pump and ran good for 2-3 weeks then lost pressure when warm. Restarted again later pressure was good, is it a plenum gasket or not causing the issue? Pickup was not blocked when pump was replaced. Seems oil is staying on top not getting to pan. Standard pump was installed, HELP.

 

plenum has nothing to do with oil pressure. its just a vac leak that sucks oil out of the engine (oil loss).

for lack of any better idea, i'd try a quart bottle of Gunk brand engine flush and follow the directions exactly. don't drive it with solvent in the oil. another option on flush is to put in 1 qt of auto trans fluid and let it idle for awhile.

edit - how many miles ?
and what does your oil pressure read ?

 

The truck has 145k on it, two different oil pumps installed same results. The pressure is 60psi and drops low enough for lifters to rattle. Might not do it each time, might even go 2-3 weeks before losing pressure again. When hot idles at 25-30 psi. Kind of wondered about the plenum thing, thanks for the insight. Mains were inspected and no signs of damage, fact is they looked great. Think flushing will do the trick?

 

i used Restore: Engine Engine treatment when mind was 20-25 idle, 30-35 when on gas.....after using pressure went to 40-45 idle, 55-60 running...Used Quaker State Horsepower Full synthetic 10w30, with mopar filter.

 

2 questions from me -
so when cold, your oil pressure is 60, and when warm its 30? that's a really big swing.

at what oil pressure do your lifters rattle ?


would a flush help? only if you have sludge build up thats restricting oil drains or passages it won't hurt and only costs a few bucks.

i've never been a fan of restore-type products, figuring they were snake oil rip-offs. but idk, if 95ram says it help his, then maybe.

let us know if anything works for you.

 

its my second time using it...i put it in, drive it about 10 miles, and chan ge oil again....i dont leave it in...

 

If you ever decide to use the ATF treatment, the detergent will not act quick if you just let it idle. You will need to drive it for atleast 500 miles on it. 4qt's of regular 10w30 and 1 qt of ATF. I have used this method on a 94 Dodge Dakota, that had low oil pressure and smoked on start up. Ran the truck for 500 and kind of hard on the motor, truck has been running great ever since.

 

Ok, I removed the air cleaner and the air cleaner is oil soaked. Looked in the plenum and looks wet inside. So it looks like the plenum is coming off. I will have to also flush the engine when done, looks like build up in valve covers.

 

oil on top side of air filter could be PCV not working, and oil suction coming up through what's supposed to be a vent to the valve cover.