my car's engine temp. stays within the two notches on the guage (not the blue or red marks, but the notches between them. But there doesn't seem to be a pattern to how and why it varies between these temperatures. I feel justified in diagnosing this as a faulty thermostat. Would you agree? And I want to know if this is bad for my engine and I should go out and replace it right away. Also, I was looking at Bav Auto at thermostats (wouldn't buy one there, don't worry) but they sell the Aluminum thermostat housing, what does this do? is it a good idea?
<img src='http://img268.echo.cx/img268/1430/zkwsig23iq.jpg' border='0' alt='user posted image' />
1996 328is Black
Suspension: MB Motoring 18x8, Kuhmo Supra 225/35/18ZR
Audio:Eclipse CD3414 HU
Lighting: ZKW W/ DDE PLUS