Where is the thermostat on a BMW 325?

Answer 1

thermostatWhat is the year? If it's an e36, its where the two radiator hoses meet in front of the engine above the belts.

My car is a 2002 325 i, e46 model. 90k miles and never overheated. Read below.

here is something else i am looking at on mine. I replaced the coolant reservoir yesterday, but after taking the old one off the car, realized that there is some small enclosed thermostat located under the reservoir. The new reservoir slides down onto the hoses and junctions, and into this bottom hose there is an enclosed and very small looking apparatus. Measuring about 1/2 inch across and about the same in height, and sitting on a spring, the one in my car was sitting crooked, and this resulted in the new reservoir not seating properly and fully down on the connections and hoses. Inspecting it showed that it should be fully upright and let the reservoir seat down on it. A VERY tight fit. Attempting to straighten mine out, and being gentle, it cracked and came apart in my hand.

Now I am screwed, as NO ONE has ever mentioned this particular part in any discussion that I have found. What exactly is it, and how important is it?