Hey everyone, nice forum youve got here. My GF has a 2008 Jeep jk thats using a considerable amount of oil. This jeep was bought brand new in 2008 and has always been driven on the street at an easy pace. Pretty sure Ive never seen the rpms go over 3,000 before. Oil has always been changed at a 3,000 mile interval.

I've read on several forums about the jk using oil but Ive yet to see a common solution nor do I know what the solution is. In the beginning of this year (2013) I noticed her Jeep was low on oil. Didnt think much of it but I topped it off. When the time came to change the oil, it only had around 4 quarts of oil in it. Cant remember the mileage when I topped it off or anything. We took it to the dealer and they did their little oil consumption test. They always fill it up right to the top of the safe zone on the dipstick, which I think is high but whatever. After 1,500 miles it had used over 2 quarts of oil. Found out at that time that it had the life time warranty, so they put a new (reman) set of mopar heads on it.

Also at the time, it was leaking antifreeze something awful. It would leave a large puddle of antifreeze everytime she parked for over 30min. The puddle would be at the rear of the engine and I couldnt for the life of me figure out where it was coming from.

Anyway, they changed the heads and the oil consumption SEEMED to slow down. The antifreeze leak stopped so I assume it was the intake manifold.

Fast forward to now, its using antifreeze again and using oil again. No puddles of antifreeze but its using it much slower than before. Took it several months to use whats in the overflow tank. Ive noticed this engine rattles like mad under load. Going up hills and accelerating it rattles, sounds just like pre-detonation (pinging). After they replaced the heads it stopped rattling. They said the oil is being burned b/c of worn out (bad from factory) valve guides. Which in turn ruins the valve seals. No smoke is ever seen, even on startup. I know, the cats burn it off. At start up a cat is cold and will not burn off the smoke so if the valve seals are bad it should smoke at startup. Would bad valve guides cause the valves to rattle? The rattle returned soon after the new heads were installed(~1,000miles or so later).

No leaks are seen anywhere.

Today they replaced the water pump, they say thats why the antifreeze is disappearing. Never seen any leaks from the water pump but hey, its free. They did another oil consumption test and say its not using enough for Chrysler to do anything, which I understand, they wont get paid if its not using whatever amount. At 2,500 miles the oil was between the bottom of the dipstick and the bottom of safe. I thought for SURE that would be enough to get them to continue working. I would think that would be more than 2 quarts but idk.

Just sharing my experience, any input would be amazing. Ive yet to check the compression but I do have a compression gauge so I may do that. May try to do a leak down test also. The dealer says not to worry with it, they didnt say to let it run out of oil but they said "hey, if anything happens Chrysler must fix it." Theyre great people to deal with.

For those of you that say, "check your oil every day, using some oil is normal." You're idiots. Plane and simple. No engine should use oil with this many miles. My family has had jeeps since 1994, and I still drive that 1994 Jeep. Its a 4.0 zj with 201,000 and it uses absolutely NO oil. My kj uses no oil, my 5.9 zj uses no oil, my brothers 99 xj uses no oil, my brothers srt8 wk uses no oil, my moms 06 wk Hemi uses no oil, heck my dads 96 honda accord with 250k uses no oil. Good engines do not use oil.

Jeep currently has ~76,000.

 

Take it to another dealer?

 

Many deal with this, and the oil consumption test is always the place to start. They should have also changed the pcv valve. Are you still running 5w20? If so, go with something thicker like 5w30 or 10w30. The pinging is also common with this issue. Try to run some Mopar CCC to try and clean the valves up some.

 

Fought my 08 for oil burning for a couple years. If it is not bad, then change the PCV valve....it does help.
Mine was burning a quart every 1500 with Mobil 1 but when they did a consumption test it burned a quart of the dealer's oil every 500 miles. The dealer tore the motor down and found two cylinders that were out of tolerance....Chrysler already knows there are many out there with the same problem but it is typical deny,deny,deny. The dealer installed a new 3.8 short block and amazingly the new motor calls for 10w30. I asked the dealer if that was right and he said that was a better oil for this motor. The original motor had to be 5w20 because of regulations but on a replacement motor they can use what they want. new motor doesn't burn a drop

 

Im pretty happy with the dealer so far. They did put new heads on it without any question. Yeah still running 5w-20, thought about trying 5w-30 but haven't. Odd your new engine calls for 10w-30. They didnt say anything about the pcv valve. Ill check it out.

Some would frown on it but if i knew it wasnt low enough i wouldve made sure it was low enough. If something wasnt wrong it would be different, but obviously something is wrong.

 

I have a JKU 2010 and I'm loosing 1 liter every 1000km. They are doing a test now on it and they check it every 1000km.... Don't know what they will do after?

 

Probably tell you it is in spec and do nothing. Watch them when they check the oil and make sure they don't top it off..

 

My friend changed his PCV valve, and is seeing if that works right now. It is an '08, and when he pulled the valve out it wouldn't rattle. Dotta Jeep in PA says that even if they rattle it still might be part of the issue. I personally have a '12, and I just could never bring myself to run anything below 10/30w. I just get the receipt printed for 5/30w where I buy the oil (Penzoil, Ultra).

 

I would never run anything less than 5w30 in these motors.

 

I have a 2008 unlimited that is going through oil... I have researched this idea on other automotive threads... It seams that the ford mustang also has a very similar issue but in high performance applications when they run high rpms... Search it on the Internet...

For jeeps I keep reading that the solution is a new PCV valve and lighter weight oil... Well not convinced, the PCV valve is simply that a valve to prevent backfire into the motor... The PCV system in short is to allow volatile gasses built up in the motor to burn off in the combustion chamber... See my next post for a complete explanation of the system...

Assuming that then 3.8l internals are good ... The lost oil has to be in a saturated air mixture leaving the PCV system and heading into the intake... There has been many post on this site of people taking their throttle body off and finding large quantities of engine oil in the intake... So the solution should be the same as being used on the fords mustang racing application... PCV per-filter and oil separator... I will be working on a plan this next few weeks to test fit the JLT pcv filter mustang solution...

Please feel free to add thoughts to post... By the way I run 2300 rpms for 60 minutes per day... Higher rpms means more engine pressure and more oil/PCV air saturation... Just hope I'm not to late to save my motor... Noticed blue smoke yesterday with colder temps....