After some research here in the forum, I am pretty sure that my heat exchanger is leaking. Symptoms: white, odourless steam from the ventilation. Discs will not be free or fogged fast My foot mat is dry, I have no increased cooling water consumption. Today I looked more closely and took pictures. My request: Could you look at this and confirm the defect? I don’t want to change the heat exchanger if it is something else (quick coupling). On the pictures you might think that you see run-out cooling water, but only small, dry rindsale. I also read that you often have to pull a screw (which?) or change the O-rings. Is it worth the attempt? What do you think of the heat exchanger from Polar Parts (http://www.ebay.de/…/291795207624?…). Looks as if there are all the necessary seals there. When changing: Where should the cooling water hoses be glued off? In the engine room, directly before the quick coupling?