Engine Cooling problem
1999 Pontiac Grand Am Automatic
I've been having problems with my " Low Coolant" light coming on. I checked it once after it first came on, and the mechanic said that I shouldn't need coolant, but he topped it off anyway. It drove okay for a couple of days and then the light popped on again. I let it go a little longer this time and then took it in again when it started to run hot (which it doesn't always do when the light comes on).
Today while driving to work the light came on again, and I just kind of shrugged since it had been about a week since my last coolant top off. But then I looked at my temp and saw that it was running pretty hot. I turned on my heater to max to help vent some of the heat but it blew out cold air. After a couple of minutes, the temperature needle dropped to below 200 (and I actually watched it happen over the course of about 5 seconds) and the heater started blowing out warm air again. The temp started rising again and then the air turned cool again.
I do know that my radiator cap is messed up. The cap itself appear intact, but the part that plugs the radiator separates from the part you use to unscrew the entire cap so that you need to pry the plug out with a screwdriver or something like that. I get that such a mess up could foul up my coolant sensors, but would that it also effect the heating and cooling system in the car?