Last night I find my thermostat is dead. While driving to dinner I see the temperature guage much lower than usual. It hasn't been this cold around here since March. Today, I look into it and 50+ MPH with the heat on, the guage drops below the left white tick mark. Turn off the heat, or stop and go traffic and it starts climbing to it's usual spot. So I need to replace the thermostat.
Anything else I should be doing while im in there?
Is the blue antifreeze from BMW really worth it?
97 328iS, Manual, Stock