| 2001 E46 Coolant Systems upgrade ? I have 2 questions. I just bought a 2001 330i that I am planning to replace all the major cooling system components. I was told by a local BMW specialist that I need to replace the transmission thermostat as it will break when I remove the expansion tank. Question #2 is that I was told by the same people that I should not get a metal thermostat because they are likely to leak and that the metal and aluminum engine do not jive. Something to do with non-like metals causing corrosion. Anyone have experience with this? Suggestions? |