Running cold on the highway....why?

[johnny_boi20]

So my 330xi is running at normal temp in town but when I get on the highway the temp gets almost into the cold section on the temp gauge. Any ideas what could be wrong???

[drz]

Your thermostat is not working. It is staying open all the time, so cold coolant is flowing at all times through the engine. If it were working, it would regulate the flow of coolant in order to keep the engine at the desired operating temperature.

[FCPGroton]

+1, Had this issue on my motorcycle. The thermostat was cracked on one side so coolant could flow all the time. Just replace it and you will be all set.

[Ruffler]

Originally Posted by johnny_boi20

So my 330xi is running at normal temp in town but when I get on the highway the temp gets almost into the cold section on the temp gauge. Any ideas what could be wrong???

I had the same problem on my 2005 325i. Thermostat was the problem. Got it changed; all ok now.

[Torque]

+1 to everything that was said.

I had the issue with my 318 as well with it; didn't bother me during the summer but I addressed it a few weeks ago as the winter is approaching quickly.