I happily owned a BMW E36 for many years and it was probably the most reliable car I have owned. I purchased a BMW E46 recently but was warned by my local mechanic that the cooling system in the E46 resembled a large plastic toy with a lot of plastic parts (you know what happens to plastic toys .. they break). Sure enough within a few months the plastic coolant expansion tank decided to crack. When it was being replaced i was given the old broken plastic transmission thermostat (in a number of broken parts) as a momento. Some months later the radiator itself decided to leak (yes.. also from the plastic part of it).. I was told a new radiator was needed. The new radiator arrived and, guess what, it was the wrong size. It had a 15mm flange at the top & bottom rather than the 10mm flange that mine had. This meant that the old plastic component that housed the transmission thermostat, etc did not fit. At the moment I have pushed the E46 in the back shed whilst I wait for either another radiator or another plastic part (who knows which). But I started up the old E36 (started beautifully with a new battery after nearly 12 months the back shed). Why did they change the coolant system from the old E36? Anyone else having this problem? Also beware when ordering a new radiator for a E46 that they are in fact the same size.