So I got a new 2011 JKU Rubicon, 6spd with about 2000mi on it. I changed the oil at 1000mi to conventional Valvoline 5w30 with a Fram tough guard filter. Vehicle is stock. Idling sounds fine, but when you press on the gas to go it almost sounds like a small diesel engine under the hood. Besides that it runs great, just sounds funny. Any thoughts or is this normal? Should I switch back to 5w20? Thanks.

 

Can you describe the noise a little better ? Valve clatter perhaps ? Knocking etc.. 5w30 will be fine just do not let the dealer know or it can void your warranty. Some peeps think the 5w20 is actually too thin of an oil and a viable reason that the 3.8 has been troublesome for alot of people.

 

I guess the best way to describe it would be a knocking noise under acceleration. Again the jeep runs fine gets 18.1mpg according to the computer, does not idle rough, no idiot lights came on.

 

It's a quick knocking/ticking sound if that helps. I know its hard to diagnose a sound over the internet LOL

 

Did you go from a smooth quiet sound to a sound like your jeep was a smoker, like a raspy voiced lady? Mine just started doing that at 71k miles.

 

i have a afe intake on mine, and when I get into the gas sometimes I think its gonna explode haha....but thats the crappy motor trying to produce all that powernottttt

 

It sounds like its running kinda rough but its not I think its just the motor acting normal. I just took it for a ride sounds like an exhaust leak but I doubt its that being new. Who knows, thanks for all the input, I'll keep wheeling it until it becomes a bigger problem, if it is even a problem...LOL

 

Given that it is a mass produced vehicle, I would not assume you could not have something like a cracked exhaust manifold just because it is new.

 

Sounds like spark knock. There are many threads on here. Unfortunately a very common problem with these motors, although they shouldn't do it at all

 

Mine makes all kinds of grousome sounds under acceleration, it ticks like crazy, unbelievable amounts of clatter (marbles in a can) ect ect.. It is getting VERY loud. I get looks from everyone at intersections when I leave the red light because of how hideous it sounds.. I'm fairly confident one or more moving parts inside the engine is going to come out of the exhaust.

I'm probly going to remove every piece of shit heat shield on the exhaust and put heat wrap around the bastard all the way past the cat and torque the piss out of any and all bolts I find along the way that are near the exhaust.. Truely embarrassing and very annoying, but sound aside, it seems to run very strong, and that being said, I'm going to continue driving it until the exhaust falls clean off, or the motor implodes in on itself.

Mabey it just needs a mud bath.. perhaps if I wedge enough mud up inside the exhaust, the rattling will stop.