I've just had my thermostat and seals replaced on my 2014 S3 while it was in for a service and MOT, they noticed a bit of residue below the thermostat housing and recommended replacement so I've had it done before it gets worse.
The dealer also gave me a bottle of coolant in case it burps more air out the system over the next few miles, the S3 is notorious for air in the cooling system. Not under warranty so cost £670.
The dealer also gave me a bottle of coolant in case it burps more air out the system over the next few miles, the S3 is notorious for air in the cooling system. Not under warranty so cost £670.