Help 2008 Jeep smells like burning rubber every so often
I bought a 2008 diesel Jeep a few months ago. My wife drives it mainly. She came home and complained to me it smelled like burning rubber and over heating. So I drove it around and smelt nothing. I figured she was smelling the exhaust.
That was 3 months ago. About 2 week ago I took the Jeep for a 6 hour road trip. About 3 hours in I smelt the smell. It was very very strong. To the point I pulled over to make sure there was no smoke from the engine bay. It smelt like burning rubber to me.
I got back in and noticed I could only smell the smell in the cabin if the AC was on. If I turned it off, no smell.
So over the next 2 weeks I paid attention to the jeep and drove it abit. No smell. I called the dealer I bought it from since it was under warranty to let him know and that I was taking it into the shop.
Got it into the shop today. Took the mechanic 3 hours of driving and letting it idle before it would smell for him. But he said when it started to smell, it was really strong and filled his whole shop. It spent some time looking, but found nothing leaking, nothing burning, nothing wrong at all. He figure's it's part of the emission system and that it's operating normally. He desribes the smell as the smell you get from DEF systems. I've never drove a vehicle with DEF, but I'll take his word for it.
Can anybody add some insight to the smell? If it's normal I'm ok with it, but I would like to know what causes it to smell like this.