[dotmak66]

Hello everybody. I've had any issue recently with my F20 116i Pre-lci where the car overheated and had coolant leaking out of the expansion tank.

After taking it to the mechanic we found that the thermostat was faulty and replaced it. The mechanic also noticed that there's a whole in the screw valve ( black thingy in the expansion tank) and told me that he's ordered the replacement part and will arrive next week, even though i shouldn't have a problem till the part arrives for replacement.

So i pickup the car, did some spirited drive and also i needed the AC for a bit since the glass was getting blurry. After spirited driving for 3-4 minutes, i got in traffic for around 10-15 minutes and then parked the car. Upon parking i saw this horror:

Any ideas ? We did a compression test and everything seemed alright.