Check Coolant light on when cold
 

Ok, my roommate has a 1990 Mustang 5.0, the problem is this. Recently in colorado we have started to get into cold weather. Only when its cold out and his car is cold will the Check coolant light come on. What would be causing this, and is it an easy fix?

Appreciate any help.
Thanks guys

Sometimes the coolant level sensor will crap out and send signals, but in your case, you probably just need to put more coolant in.

The sensor hangs from the top of the coolant overflow tank, and when the fluid level drops and the coolant dries off of the sensor, the "check coolant" light comes on. When your car is cold and there your coolant level is a little low, the sensor will dry and turn on the light. When you drive, the coolant level in the overflow rises as the fluid expands and wets the sensor, and it turns off. Does this to me all the time.

--nathan

Thanks
 

I appreciate it alot. Thanks for the help.