I just bought a 2004 996tt. I have notice coolant loss. Had it pressure tested and results came back ok. I changed the coolant cap and it ends with 04 now. Car does not overheat and no lights come up on dash.

I did notice that at the base of the new coolant cap, there is now white/pinkish residue as if its leaking again. I drove about 200 miles (slow and in traffic) and had to add about 1 gallon of coolant.

Is it possible to lose this much coolant by evaporation through the coolant cap?

Thanks for you help.

 

These cars are known for hairline cracks in the coolant reservoir that are not readily visible. The residue on the cap is pretty typical.