The 4.7 & 3.7 were designed with 5w30 in mind, they (most manufacturers ) went with 5w20 for fuel economy and government regulations.
Most of the older engines have 5w30 written somewhere, my 06 motor did, the 2012 liberty engine had 5w20 on the oil cap instead.
I'd say it's safe to use the 5w30 on the 09, not sure about the anything heavier. It'd have to be a very warm climate, I don't think these motors play well with thick oils, but don't really know.
This is what I found upon my research, which ended up being mostly about the 3.7 in the Jeep Liberty. I am planning to go ahead to 10w30, because being in Houston, we never approach zero degrees, lucky to be below 32F for 24hrs. I have heard of guys running heavier weights (10w40, 15w40), but I won't go over 30 weight since it seems that would be enough extra protection for me.
The manufacture spec on oil usage seems crazy, some of it is to keep was warrantying the new engine which take time for the pistons rings to seal right.
Went through some of this on a rebuilt ford motor, it did get better by the third oil change but it's easily down a quart by 3500 to 4000 miles, but the standard is right there in the owners manual. Nothing they would do about, probably nothing to be done.
Agreed. My 95 Mustang GT was run with supercharger from about 17k miles through over 125k miles, and even with a fair amount of blowby on the rings, I have never approached have more than 1/2 quart consumed over 3k miles. So, for a stock engine with regular oil changes and maintenance, the spec is nuts.
I don't remember what your history is with this motor, I would try a few additives as suggested but definitely would not run a motor flush, it's what screwed over our 3.7 that turned out to be gunked despite the carfax record of recent regular oil changes .
If you're curious about the condition inside the motor I'd remove the oil filler neck, it's the easiest way to peek at inside the cylinder.
you've got the skinny filler neck right? If it's the wide mouthed bigger oil filler (02-06?) there is a baffle inside that pulls out that will show gunk if there's any built up.
Didn't think to do this before, but I will definitely do this out of curiosity. I would imagine there it is not gunked up since I have been running synthetic since I bought it at 17k miles.
The liberty guys know a hell of a lot about the 3.7, that's where I went to learn as much as I could about the 3.7. For a liberty the easiest way to check inside the 3.7 is remove the valve cover, on the commander it's a pain, even when I was 3/4 of the way removing the engine with everything out of the way the passengers side was hard to get free. Don't know what others experienced doing the same job, it could be the motor mounts were shot.
With no leaks sounds like you've got a well looked after 3.7, probably better to try small incremental changes like additives or oils and see how it does over time.
Yeah, since it is the Liberty's big engine, it seems to be the most popular. I looks like some of those guys have done power adders, etc. They will likely be my source for the 3.7 from now on.