I have searched and read many topics, but none seem to relate to the issue I am experiencing (maybe they do but I have overlooked it or understood wrong).

I am experiencing a burnt rubber smell on certain occasions inside the car (and once while standing outside the car).

This only happens now and again, and has only started since it has gotten colder and I am using the heater (air heater, no seat heaters in my car).

I have narrowed it down to only happening when I have the heater on, and although it has happened mostly after a pushing a little under acceleration, it has happened also once or twice when driving at normal to slow speeds.

I drive the car daily to work and back and this has happened maybe 6 or 7 times in the last 5 weeks (since I started using the heater).

The smell is very similar to that of burning rubber when wheel spinning. When experiencing the smell, I have checked under the hood and also in the trunk, but the smell was not present, only inside the cabin (and once when I got out, but that could be because I opened the door to let the smell out).

As I say, it does not smell of electrical burning (I do have experience with that smell ), nor does it smell like engine burning.

Can you guys recall anyone having a similar experience so I may be able to track it down??

Many thanks as always!!