E36 - part id help needed ?sensor?

[hillsider]

Greetings,

So my 95 325Ci overheated yesterday, turns out it was nearly empty of coolant, due to a broken part. A small solenoid (non-electric) or sensor of some sort. It is located in the lower portion of the air filter box assembly, and has a collant line (approx 3/8") going into and out of it. Inside was a small spring. This small plastic housing was broken, so that the coolant line just emptied to the street! It was easy enough to remove, only 1 screw and two hoseclamps. But I do not know what it is, I figured I would try my luck here with the guru's before hitting the library tomorrow to id the part for ordering. Thanks in advance,
forgive my ignorance,

[Dudesky]

It's a thermostat for heating the air in the throttle housing during the colder months. Try part #13 54 1 730 682.

[hillsider]

Thanks Dudesky!