A few entries prior to yours is one from YIKES98 that shows a picture of the exhaust cooler and the soot. Mine looked just like that prior to replacement. If yours looks anything like the picture then that is your problem. Try another dealer because yours is not doing the job.
Originally Posted by rocky472
I have noticed the same soot stains on my vehicle. I brought my X5 in for service complaining about an intermittent exhaust odor. I pointed out the soot deposit during the write up. The dealer replaced my air charge temp sensor and stated the soot deposits are normal. They printed the attached Service Bulletin as proof there was no issue. Stated they couldn't detect the exhaust smell.
I drove the vehicle another week and the smell was driving me crazy. Returned the vehicle to the dealer and they said it was still an no trouble found. After playing with the recirculate setting I found the smell was happening when the HVAC switched to the recirculate mode. Leaving the vehicle set in fresh air mode helped. I checked the interior filter and it looks new, no deposits.
I have since noticed the odor during lower speed driving (45-60 mph). I returned the vehicle to the dealer and demonstrated the smell. They downplayed the issue but agreed to try again. The X5 goes in again tomorrow for the third attempt.
This is my first BMW and so far I am not impressed. This vehicle has been in the dealership more times in 20,000 miles than any other car I have owned. I work for an automotive component supplier and know first hand what is like to deal with foreign customers, especially German. All the extra effort does not seem to translate into a better quality build.
2010 X5 35d