2001 330i cooling system questions...

[WG330i]

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?

[Lord Vader]

Woah woah woah. They told you to replace the transmission thermostat? Find a new shop. Now. Their is no such thing, and saying that it will break when you remove the expansion tank is a lie. Unless you meant to say something else, their trying to rip you off, badly.

The thermostat housing was plastic and should be replaced with a metal one. Thermostats themselves are metal anyway. The engine used several alloy components so I wouldn't worry about mixing metals. Theirs enough different metals in the engine that it won't make a difference. Just remember that aluminum is softer then other metals.

Worry about the plastic stuff first. Thermostat housing, water pump impeller, expansion tank. But also the fan clutch and rad hoses. The radiator is usually the strongest link in the cooking system, but if you still want to replace it the Mishmoto rads are the best for BMWs. And they are available on eBay. They come with a good warranty too.

Any other questions just ask.