I had this 3 times so far with just 400 miles on odo.
Though all these miles are in extreme cold temps and snow, if that makes any difference.

Pulled in the garage a short while ago, and immediately smelled a "heavy burning". Of course, I went into a semi panic.......just took delivery of my 35d last week, and just hit 400 miles on the odometer.

Popped the hood, didn't really smell anything of significance in that area, went to the exhaust, tried smelling there, but it appeared to have dissipated into the garage.(remember, I am in a semi-panic) The entire garage smelled like something had been burning. Then I finally recalled reading a thread awhile back that mentioned a particulate filter, and burning of soot at high temperature. (it pays to read these threads!). So, opened both garage doors......let it air out........took the X5 for a quick trip to the store....no engine lights or anything abnormal.......got home.....looked up the particulate filter issue in the owners manual.......thought....uh huh! And, better yet, found this thread which pretty much validates what was going on. (soot burning....I hope)

I came close to calling the dealer, and having them come get it and check it out........but I am much calmer now after reading this thread. You guys do a great job is describing these issues.......:thumbup:

Luckily, the wife wasn't home at the time, or I would have been in a panic for real........as it is.......now I will warn her for future aromas in the garage.....

If anyone thinks I missed diagnosed this issue.....please let me know.......

Thanks again for all the posts......

We've had two "burn offs" that we've been aware of - in two months of X5d ownership. In a not very well sealed two vehicle garage, the odor lasts - at most - 10 minutes. To this Italian-American nose, the odor is very similar to burning paper or cardboard. Easy to understand how the panic-button would be activiated if you didn't know wa' wazzup!

I smelled it twice while driving, but after I put auto air recycle on, I haven't smelled again, atleast not inside the car.

I've noticed it also cuts down for fuel mileage as well. No, you didn't miss anything, it's normal...

Craig

Good thought that, about the recycle because the only time I am reminded of the diesel is driving along sometimes with the AC blasting and smell that smell...

Ah, looks like you might be getting the Nitrous Oxide treatment. Thats an added advantage of going green, you get a good laugh when you get home ;)

Just kidding, but I am guessing from my limited chemical engineering background that it is probably an oxide of Nitrogen or Ammonia NH3 due to the Urea cycle in the engine exhaust.

More likely to be the diesel particulate filter, as it produces a burning (sweet, caramel) smell during the regen cycle. Details posted above in post #27.

Another confirmed case here - actually took my diesel to the dealership. They obviously don't know about this, as they spent a day poking and prodding looking for any leaks.

Good to know - thanks for the info1

Not just BMW. Self-cleaning DPFs are more or less the norm now on late model turbo diesels.