Here in Canada, vw covers heating core for 10 years since car purchase date, and I believe that turbo is covered too. They replaced mine two times, all I can say that its very hard to prove that the problem is with heating core,dealership would charge you for check up and if they figure out that the problem is heater they will not charge and replace a part for free. I had a situation that I had to argue with and convenience them that's s the problem with heating core. Last time they kept my car for a couple more days to test it, as I didn't agree that anything else is wrong with a car. I know thay have to make money but not on this way! I don't know if we here in Canada have any authority to complain to, maybe we can fill out request for recalls, and see what will happen if anything!