Asking this question because people on the Jeepforum.com arent 100% sure off hand. My 5.9 consumes about 1 quart every 3k miles, has for the last 5 years ive owned it.. It had 118k now has 180k. I did the plenum fix 3 years ago and it didnt help and my plenum is dry and clean so my Jeep just burns a quart every 3k.. I put in half a quart at 1500 miles so i can keep it topped off.


I was told this was normal/acceptable consumption, at least from what i remember.. but does anyone know what the FSM states ?

Totally fine. Mine has burned 1-2 quarts its whole life. When it drinks more, I know its time to change the PCV valve (Mopar). All engines burn oil, others more than some. My dad is happy when his Cat only uses 2 gallons per change in his W900.

I wish mine only burned that much oil......

Tell me about it.... Mine is most certainly what I would consider "excessive".... I go thru a quart about every 100-150 miles.... Only smokes at startup.

Same here. What you diagnosis as the cause?

Before I developed a minor leak that I haven't yet isolated, my 5.9l consumed between 1/2 and 2/3 quart between oil changes. It tasted like doing mostly or all short trips increased consumption, while doing mostly road trips decreased it, but that could have been an artificial flavor.

That's usually valve seals. Throw a blue puff and away you go until next time you do a cold start.

i went from 2-3 quarts every 3k miles prior to plenum kit to about what you are experiencing now -after the fix. I am at 151k miles now. I would say you are doing good.

I have almost 200K miles on mine, so, I am quite sure the valve seals are shot. I have my doubts about the valve guides as well, not to mention piston rings..... I haven't really done much diagnosis on it, mainly because even if I find what's wrong, I can't afford to fix it. I have another motor hanging on the engine stand in the garage, the plan, hopefully, is to 'freshen' it up this spring, and install it......

so far 158kish and maybe a 1/2qt every 5k