We picked up a 92 325i yesterday. Has every maintenance record. He did a ton of stuff to it. Even a new headliner, control arms, radiator, waterpump, etc.. I love how sporty it is also. My 525i is more comfortable though.

Anyways, I noticed that it goes up to operating temp, and then will fluctuate between the 1/4 mark and 1/2 mark. Most of the time it stays at 1/2 though. Why would it fluctuate? Should I replace the thermostat?