I've been ransacking the forums looking for one on this, sorry if I missed it. When my engine is cold, I notice a burning smell under heavy acceleration i.e. merging from on ramp. At first I just thought it was new engine smells running out like a packing grease burning off something but at 1,800 miles, it's still there. I'm about to do my first oil change this weekend. I'm going to try out the 5w30 as the temperature rarely drops below thirty and frequently hits the low 60s during the day. Has anyone noticed this or once again am I just being overly paranoid?

 

ive never witnessed that smell before

 

Not sure with such a new engine... Have you checked your oil level? Is the smell distinct? Like, how you can tell the difference between plastic burning vs metal heating up, etc. I'd suggest maybe changing out your oil a little earlier than the typical 3,000 mile mark and see if the smell is still there. It's most likely just the new engine breaking in and stuff (but then again, im not super-mechanic). Sorry I couldn't be more of a help...

 

I took my 2012 with 5k miles on it with a horrible smell coming from the vents when I it gets warmed up. The conclusion was f'n stickers on parts of the engine and drive train burning off.

 

i also have a 12JK and can't figure out the burning smell from coming from the vents. I dont have much faith in the dealership do to past experiences. Before my lift and tires I drove through a 6" deep puddle of water on a main roadin the rain and my jeep stalled out. I could'nt get it to stay runnning, it would just stall out. I checked the air box for water and there was none. So I looked underneath for and damage but there was none. So i had it towed to my house and called the local dealer. Right a way the service advisor said to call my insurance company thay the motor was hydro-locked......I told him that that was impossible because it starts up but would'nt stay running.... So i had it towed to the dealer and a couple of days and phone calls later it was fixed. When i asked what the problem was they said I had ripped the fuel line off the frame rail.....I said hows that possilbe it a little puddle and started but would'nt stay running, and there commercial shows it driving a cross a DAMN RIVER. I said i have never heard of such a thing please alborate. No matter how I asked they would'nt give any more info and the repair order had nothing billed on it. I have since stopped going there for oil services and now do them at home and get the oil filters from another dealer. So like I said I have LITTLE Faith in the local dealership. SO need less to say if any figures it out please, please, please post the culprit.

 

Jeep states : Trail rated..one of the required items to achieve the trail rated badge is water fording in up to 20"of water..

 

Bad to do right there. No matter what it is I NEVER lay into anything until it is @ operating temp. Unnecessary wear on parts like piston rings and rod bearings usually are the ones to suffer there.

But could the smell you are getting more most than likely be the catalytic converter being loaded up and "blown out" via heavy accel. Under operation on its way up to temp, engines usually have more blowby "cold" than "hot". That along with common condensation in a converter that is only just been woken up has all that particulate matter within.

Now whack it with higher revving hotter exhaust gases being shoved through it and you will smell that stuff being expelled. Oddly enough for some reason My JK smells after a hard pull inside something fierce when I have the vent on recirculate and I am hammering down the highway????

 

But that wouldn't smell like burning plastic.

 

Took mine in for a burning smell, they said there were stickers on the engine/exhaust. It sometimes still smells like burning plastic.

 

mine does this. 5300 miles. It's REALLY bad when i lay into it.