Yesterday the heater in my car just suddenly came on by itself, even though I hadn't touched the controls and everything was set to normal, outside air was cool. I turned on the A/C as it was getting quite hot in the car, and about 5 minutes later the engine light came on. I turned around and went back home, parked the car in the garage.

This morning I started it to go down to the dealer to have them check it out; engine light is still on but the heater problem is gone.

After several hours of waiting the service guy tells me they can't duplicate the heater problem but this is normal when the engine gets too hot...the computer turns the heater "on" to help pull heat out of the engine to cool it off. I'd never heard of anything like this in my life but I didn't say anything to him. They had to order a part of some kind to fix whatever the engine light was referring to, so I have to take it back once the part comes in.

Has anybody heard of this business of the heater coming on automatically to cool an overheating engine? BTW: the gauges all showed correct readings.

 

I've never heard of the automatic response... But, I do know that turning on your heater can help drain a little excess warmth as a last resort. I'm sure someone else can chime in with something more definite.

 

Someone recently posted a thread about their heater being on no matter what they did, even turning on the A/C. Can't seem to locate it atm.

 

I had a car that would overheat and if I put the heater on full blast and then of course roll all the windows down, I could get the temperature to come down quickly. This wasn't so bad in the winter time but it sucked during the summer so I traded the piece of crap in.

 

Just sounds like good engineering on Mazda's part. Automatically turning on the heater could save your engine.

 

Hehe, been there too, had to run with the heater on full blast all the time during summer. The heater is really good in a 1983 SAAB 900 GL during winter, but at summer it is spectacular...

Cheers, Niclas