Originally Posted by Casca
Nice write up and no doubt it will be useful for some that have leaks (although they may want to try loosening the hardware and retorquing it, clean it and inspect after XX miles/time if they feel lazy or have difficulty getting the new gasket), but this is not really a wear part and there is no reason why BMW would give it a second thought for the maintenance program. It's one of those "if it an't broke, don't fix it" parts.
Thanks... Well, the reason why I would recommend replacing it out of warranty (at least before 100k miles) because apparently the gasket deteriorates and chunks into the cooling system. (possibly clogging up your thermostat)
If you do a coolant change and see black chunks in the fluid, change this gasket.
btw, this gasket will not last forever, its made of rubber. Mine @ 100k was totally flat and squared into the grooves when the new gasket was diamond shaped and almost an 1/8th of an inch thicker.