How is the level in the expansion tank?

 

Exactly where it should be.

 

OK.
I was thinking you might have a very small drip that is landing on a hot part of the engine/connected components and burning off. I had this on mine @ a coolant control valve. It would drip onto the engine area and give a smell but I never saw any leaks and the expansion tank didn't seem to drop past the full level. It was a very small drip.
Some others have also mentioned the expansion tank cap seal not sealing properly and getting that smell.
Either could be a possibility but hard to say over the net.

 

How were you able to find it? I will mention it to the shop that services mine next time I go in for an oil change!

 

Waterpump has already been replaced by VW dealership prior to my purchase.

👆

 

Just making sure that I understand what you're pointing at! You're saying hat the waterpump may need to be replaced again?

 

Same story, I had to tighten the screws of my oil cooler a bit more (it's this unit with oil filter). There's nine of them, but You won't have an access to everyone. Fixed it.