[MrMurkle]

Does anyone notice a strange almost burning sweet smell after you've driven for a while and only when you do the window down. Car has done 7000 miles

[kpham]

If it's a sweet smell, then that sounds like a coolant leak somewhere.

[BigKutta]

I do get a smell after some hard driving especially in S, S+. Not sure its sweet, but its a smell

[ChrisK]

Originally Posted by MrMurkle

Does anyone notice a strange almost burning sweet smell after you've driven for a while and only when you do the window down. Car has done 7000 miles

Definitely sounds like coolant (aka the sweet smell). Check the ground before and after you park.

[MMMBRAP]

Curious......why would there be a coolant leak if only at 7K miles?

[Thescout13]

Originally Posted by MMMBRAP

Curious......why would there be a coolant leak if only at 7K miles?

Because like with anything, manufacturing processes are not perfect every time. A loose hose, a foreign object piercing the hose, etc etc etc.

[MrMurkle]

Originally Posted by kpham

If it's a sweet smell, then that sounds like a coolant leak somewhere.

I thought the same thing had it checked by garage and there is no coolant leak. But yeah I thought the exact same thing.

[MrMurkle]

Originally Posted by ChrisK

Definitely sounds like coolant (aka the sweet smell). Check the ground before and after you park.

Yeah thought same checked and theres no leak

[Bumpinjeep]

I would take it in and have the dealer look at it. They'll hoist it up and check it out. Peace of mind for your $60K+ car.

[Artemis]

During breaking-in period (1.2K miles / 2K kms) some plastic/synthetic smell is perfectly normal after a drive. But OP's car is already beyond that stage (7K miles).

MrMurkle, any such smell in the earlier stages (break-in period) or did this only occur more recently ?

A couple of M2 smell related threads (cosmoline, cavity wax, sunroof lube, rodents damage, etc.), except for exhaust fuel smell threads:

• "Fume Smell after acceleration with open window": see here
• "Crayon smell?": see here
• "First warranty issue <2k miles - turbo leaking heavily": see here
• "Terrible smell from air vent, need help": see here

Also, unpleasant odors can be experienced in the immediate environment by temporarily suspending the supply of outside air (airco: driving in recirculated-air mode).

[Got f1?]

Originally Posted by ChrisK

Definitely sounds like coolant (aka the sweet smell). Check the ground before and after you park.

This is sometimes a good indicator. However, often coolant leaks (if that's what it is) are small and are either burned off (causing the sweet smell) or get caught in the under trays and take a long time to actually appear on a floor. If ever.

Dealer visit is likely best option though I suspect they won't find it...

[ChrisK]

Originally Posted by Got f1?

This is sometimes a good indicator. However, often coolant leaks (if that's what it is) are small and are either burned off (causing the sweet smell) or get caught in the under trays and take a long time to actually appear on a floor. If ever.

Dealer visit is likely best option though I suspect they won't find it...

Totally agree, and that wouldn't bother me. However, if he has a major isssue, he shouldn't drive the car. I don't know his level of automotive comfort.

[MrMurkle]

Originally Posted by Artemis

During breaking-in period (1.2K miles / 2K kms) some plastic/synthetic smell is perfectly normal after a drive. But OP's car is already beyond that stage (7K miles).

MrMurkle, any such smell in the earlier stages (break-in period) or did this only occur more recently ?

A couple of M2 smell related threads (cosmoline, cavity wax, sunroof lube, rodents damage, etc.), except for exhaust fuel smell threads:

• "Fume Smell after acceleration with open window": see here
• "Crayon smell?": see here
• "First warranty issue <2k miles - turbo leaking heavily": see here
• "Terrible smell from air vent, need help": see here

Also, unpleasant odors can be experienced in the immediate environment by temporarily suspending the supply of outside air (airco: driving in recirculated-air mode).

I've had it the whole time I've owned the car which is 6 months. Taken it in twice regarding this smell. They can smell it to but havent found out why. Now I just drive with the window up as to never smell it. Very frustrating as I've never had this sort of problem on a new car before. Now missing my old S4 lol at least I could drive with the window down lol

[iburinga]

Got the same problem with my 2020 M2C.

The smell comes from the climate unit, which, as soon as you open a window, notices the change of air pressure and opens a valve/flap and creates a different airflow for the fresh air intake as opposed to the closed window state.

My guess is that the engine bay is so cramped, especially with the second turbo added, that the plastic of the air intake looses some softener due to the heat wich then creates the smell.

Switching the climate fresh air intake on your climate controls to closed circulation reduces the smell by a serious amount. The last button next to the Max Button does the trick (the one with the little car). You can chose between off (no light) automatic ("A" has a green diode lit above it) or Manual (The "M" has a green diode lit up above it) Switching to Manual (M) is the one you want to go with.

Sorry for the clumsy description, wanted to upload a picture, but the forum software wouldn't take it...

Unfortunately the setting self cancelles after a while, so you got to switch it in manual mode again.

When it gets chilly in the eavening, you can notice also some warmth coming to the legroom, so you definitely know it originates from the climate unit.

(this post is best read with a german accent )