Hi all, this afternoon I was checking my oil level as I typically do every week or two and since it was a little lower than it has been recently it made me think of a possible cause (and thus simple solution) to people's engines using oil.

So the poll for those of you whose engines are using oil is whether most of your driving in your JK is short (less than 10 miles at a time) trips or mostly longer trips where the the engine has a chance to get up to temperature and stay there for the majority of the trip.

I ask because always I use the recommended 5W-20 oil and typically only do short trips with my JK and I never see much oil use. However (with the recent holiday season) I have started to notice that when I do extended trips where the engine runs at operating temperature for most of the drive it does use oil. What this tells me is that the 20 weight oil at operating temperature is too thin and gets past the rings. However at the colder temps before the engine is warmed up (as the oil stays when the engine never has a chance to warm up) the thicker oil may be better contained by the rings. If it turns out that most people who are seeing consistent oil use are doing mostly long trips, I would recommend for people experiencing oil use to switch to 5W-30 to reduce this (as the oil will remain thicker at operating temps).

 

Bump to get some more replies

 

I only use 5w 20. Its what they want its what they get.

 

I actually noticed the opposite. I just changed the oil (5w-20 mobil 1 full) then drove 2200 miles in a week and used less than a half quart. I usually drive short trips of less than 10 miles and I have used 1 quart in 1000 miles. It sucks to be out of warranty!

 

I run 5w30 in mine; 5w20 isn't available over the counter where I am. Even 5w30 is expensive, hard to get and always fully-synthitic, as it's considered a winter-weight racing oil being that I live in a hot climate and freezing temps and below only commonly occur in alpine zones and some inland areas for a month or two in the dead of winter.

Most vehicles that use the same design motor as the JK's 3.8L V6 have 15w40 as the factory specified fill here, and when non-Chrysler mechanics or auto store sales assistants hear I'm using this expensive 5w30 in a low performance motor of primitive design they scratch their heads, or the ones in the know will respond "yeah, the Americans use that thin oil because they have those CAFE fuel-consumption regulations and the manufacturers specify the thin oil to achieve slightly better mileage figures so their fleets comply with the targets set, even though the motors wear prematurely and burn oil".

The only reason I'm using 5w30 at the moment is that I'm still under warranty (owner's manual states 5w30 can be used instead of 5w20); the second that's up I'll be switching to a 10 or 15w40 high-mileage oil stuffed full of anti-wear additives as I want this motor to last as long as possible, as other low-tech V6's used here (such as the legendary GM 3.8L V6) commonly last at least 150-200K or more miles before any major work needs to be done on them.

Another concern (particularly for US drivers) is that the oil manufacturers have dramatically reduced the amount of friction-reducing additives for the US market because phosphorus, used to prevent engine wear, causes cat converters to wear out quicker and so the API will only certify motor oils with very-low phosphorus levels for environmental issues (see link below).

http://www.upmpg.com/tech_articles/oil_bottle.htm

 

All great info, keep it coming!

 

I have the same 1 quart per 1000 miles issue.

I have figured out what causes it on my engine, just dont have a solution for it yet.


I was replacing my PCV a while back and when I pulled the tube off to get to it, I noticed oil dripping out of the tube. This should not happen. The PCV is there to prevent the oil from escaping. And there i was with enough blowby that i could see oil dripping out of the tube.

So the oil usage isnt due to bad engine wear etc, its blowby through the PCV and burned that way.


I hope Chrysler beat me to it figuring out what the problem is. But we need a redesigned PCV or something. It never feels tight enough when you push the new one back in. Maybe its just too loose and doesnt seal well enough.

 

I use fully synthetic 5w20 here, I noticed I lose about 1.5 quarts between oil changes as well. I brought it to the dealer for some recall crap and they mentioned the low oil to me when they did their checkup and accused me of not changing my oil properly and that I should pay them to change my oil to prevent oil loss... I'm at 44k miles and have always changed my own oil and fill to the proper levels. I use the Jeep as a DD to travel between service calls and put 1500 - 2000 miles a month on it mostly highway. I noticed the oil loss become heavier after about 20k miles. Now I just add about a quart in between changes.

 

The PCV system is there to prevent the oil from escaping into the atmosphere and onto the road.

The PVC system routes oil vapor, and other gasses, from the crankcase to the intake to be burned.

Bad rings can cause too much blow-by, which will drive an excessive amount of oil vapor, normally present in the crankcase, into the PCV system.

 

I am following. If the piston is compressing, and the rings dont seal right, allowing the pressure by into the crankcase, thereby expelling oil/vapor through the PCV.


This could be entirely true. I still have my Lifetime Powertrain Warranty. But I really dont feel like dealing with an engine swap.

anyone looking to buy an 07, OME lift, brake lines, extended swaybar links, Gobi Rack with ladder.... HAHA