Coolant smell, can't find a leak

[BH2000S]

Thanks for all the great advice. I have not had time to jack the car up and check the water pump yet. I did check the burp valve (aka coolant bleeder valve?), totally clean. The expansion tank cap seems to seal fine but the threads seem a little wonky and the part number ends in 02 so I'll order the $27 updated Porsche one from Pelican. I don't really smell anything in the trunk.

I don't know if the water pump was replaced with the engine. The receipt notes a lot of hours cleaning coolant out of the oil system but not the water pump. I need to track down more info from a dealer.

If it is a small seal leak, I would be tempted to use a cooling system sealer but I'm guessing that will just cause problems down the road with a Porsche.