i have dodge ram 1500 with a 5.9l magnum. so here is the history the engine was swapped in less than 2000 miles ago. new plenum gasket, new valve seals, lapped old valves, new head gaskets. etc. i noticed it burns about a quart of oil every 1000 miles and smokes a hint at 4000 rpm. did a compression check, all cylinders where 127psi + or - 2 psi. did a leak down test today 0% leakage on all cylinders. oil pressure is 40 psi, engine vacuum at idle and 2000 rpm is 18", less than 1 psi of blow-by in crank case at 2000 rpm with pcv disconnected and plugged. with pcv connected there is no pressure/vacuum in the crank case. with filtered air inlet to pcv plugged there is 5" of mercury... any ideas? im begining to think oil rings???

 

These things eat oil for some reason, one thing you should do is install a PCV from the dealer, not one from a parts store and try that.

 

Could be oil rings, could be a torn valve seal... could be a crappy PCV valve. A vacuum gauge on an intake manifold port would show a steady fluctuation for a leaky valve seal that bad, and that's a free test. A crapped out PCV valve, well, five bucks or so at the dealership for a new one is a cheap enough SWAG.

 

Smokes a bit at 4000 rpm? I don;t know that I ever hit 4000, and I hit highway all the time.

 

Perhaps you misplaced this?

 

Thats not the norm for a Magnum or any LA 360/318 if plenum,valve seals & pcv are good....

Mine DID eat oil until I changed the plenum & valve seals and PCV valve. I haven't seen a drop of oil used in a month and a half and 3300 miles and I pound mine and see 4,000+ all the time. I went from a quart every 100 miles prior to changing the valve seals to not seeing a drop used. I've got 169,000 miles on mine.

One thing to that may help or eliminate the consumption is get a new throttle body gasket. My sisters 2000 Ram 360 would eat a half quart every 200 miles until I took the throttlebody off and cleaned it and put copper permatex in place of the brittle old gasket that cracked as I took it off (I used copper permatex mostly because she lives in the sticks and I had copper permatex on me). The tb gaskets are usually pretty brittle on these after a while. If you're clean and detailed, you can copper permatex a thin layer and that works amzing to seal! and the best part is you can drive it pretty much imediately within the time it takes you to put away your tools.

 

I'm having trouble equating a leaking throttle body gasket to excessive oil consumption....vacuum leak yes, but using more oil?

 

Yes most definitely. A variance in the vacuum would cause the pcv valve not to fully actuate because that spring inside the pcv that holds up the plunger is designed to operate at certain engine pressures under normal conditions and a tb vacuum leak WOULD cause oil to get sucked up via messing with the pcv's operation because the vacuum wouldn't be as strong to pull the plunger in the pcv. It doesn't have to be much of a vacuum leak to cause oil consumption.

Honest to goodness after I had cleaned the throttle body and put a new gasket down it stopped using oil.

 

vacuum checked perfect. and about the 4000 rpm.. its a mud truck... so its always rev'd up but i do use it to commute from nh to ny to go to school 5 times a year. i put a cup inline the pcv-intake line to see/catch any oil that might be getting sucked through the pcv valve.

 

-Have you checked the radiator for oil in it or a foam in the oil? What you describe headgasket.There easy to pinch when your putting them on.Just a thought..........