I have a strange problem that i cant seem to figure out.
When idling on D or R and have the heater on i have a smell inside of the cabin that i cant figure out if its exhaust or coolant.. a little bit of sweet smell to it but also exhaust like.

Problem stops/no smell if i put the car in park.
Problem stops/no smell if i turn AC on
Problem stops/no smell if i turn air circulation on

No smell outside of the cabin when i exit the car
Anybody have the same experience?

Audi S6 C7 2013