Stinky

[JCL]

FunfDreisig provided the text from the owner's manual, but here is some more info on the BMW diesel particulate filter.

• It goes into a regenerative mode every 300 to 2000 km, automatically. The engine computer decides when to do the regen cycle based on how hot the vehicle is, how fast and how far you have driven it, etc.
• If it completes the cycle while you are driving it, you may never notice it (apart from the rough running and reduced power)
• When in regenerative mode, the engine management is altered to keep the revs up (like driving in DS). You may notice in manual mode that the vehicle won't go into 6th.
• Fuel management is altered, so the engine may be sensed to be running roughly during the regenerative cycle
• Regenerative mode provides additional restriction to intake air, so power can sometimes be sensed to be down slightly. Throttle response is also reduced, ie it can feel more sluggish
• The regenerative mode burns off the particulates trapped in the DPF. It does this at 600 C. No visible particulate emissions should be there, but the smell will be, as a residual effect of the process
• The smell is described as caramel, possibly slightly burnt. Heavy, sweet, not like raw fuel odour.
• E90 35d owners report that during the regenerative cycle, it is very easy to burn your fingers opening the hood due to the amount of heat retained. If you suspect the vehicle is in a regenerative cycle (which is normal, but perhaps you want to prove it to yourself), touch the airbox under the hood. It will be very hot to the touch. Not sure where the DPF is on the X5, it may be further back in the exhaust.

All part of the joy of BMW diesel ownership. Not sure I would call it a character stamp, perhaps more of an undocumented feature.

[Edge647]

Originally Posted by JCL

[*]The smell is described as caramel, possibly slightly burnt. Heavy, sweet, not like raw fuel odour.

I ran into this situation....was almost waiting for it to happen and for my wife to say "WHAT IS THAT?!?!?!". I had the "don't worry dear..." answer.

Thanks all.

[Fraser]

Originally Posted by JCL

All part of the joy of BMW diesel ownership. Not sure I would call it a character stamp, perhaps more of an undocumented feature.

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

[Kief]

I know this is a dated thread, but I just wanted those of us new diesel owners to rest assure that their new Xd's aren't going to burn to a crisp!

I recently experienced this "burn off" smell when my wife parked the X in our garage and was somewhat concerned. All I kept thinking about was that thread on this forum related to some guy's Xd that allegedly burned...Anyway, the smell is very evident (at least in a garage). I thought a neighbor was cooking out. You also hear somewhat of a ping noise, like a muffler cooling off. The smell/sound seemed to be located on the passenger side, and you could feel the heat radiate near the front wheel well. Like others noted, it lasted about 10 minutes and I just kept the garage door open. I was just shy of 1k miles.