Well initially my heat was fine. I can't recall exactly when, but then it stopped working while I was trying to track down my coolant leaks. I'm really leaning towards the tstat because it feels like there is water in the heater hoses but it's just not getting hot.
2002 BMW 745Li 102k
1991 Mercedes 300D 2.5 turbo 338k
1993 Mercedes 300E 2.6 192
1995 Mercedes E420 160k