Leaking from the overflow tank cap: 2002 MCS

Hi folks, hope you are enjoying your weekend.

My MINI is leaking coolant from the plastic overflow tank on the firewall. It happens only when it's really warm out (+30.0 C) or if I'm stuck in traffic. Car has not overheated.

Is this a simple case of replacing the cap? The tank does not appear to be cracked. The local dealers were out and when I went to a parts store they tried to sell me a metal Prestone cap. Does the MINI have a second pressure cap in the system? Or is the plastic tank cap a pressure cap?

Thanks for the help.

Jeff

Is it the original tank? They are known to fail. Otherwise, its hard to say without seeing the car in person.

I have a 2002 MCS (bought new) and Mini replaced the tank sometime in the first year. It may have been a recall, I don't remember. All the first ones leaked I believe.