I apologize if this has been asked, but my manual search didn't find any references to this issue.

The problem is with a 1997 Maxima SE. When first started in cold weather and the heater is needed it works fine, for a while. After about 30 minutes/miles the heat quits and it will only blow cold air. If the car is turned off for a while, 4-8 hours or overnight, it will blow heat again when started but quit again in the same fashion.

No adjustments in temperature setting or fan speed seem to change it after it starts blowing cold.

Any assistance would be greatly appreciated.

Thanks

 

Anyone want to even guess ?

Thanks if you can help.

Dave

 

COLD ... How cold can it get in Florida? It was -22 deg F when I jumped in my car this morning.

Anyways ... Sounds like you are low on coolant. When your engine is "cold", coolant is only circulated within the engine. Once the coolant reaches the thermostat opening temperature, the fluid circulates through the rad as well. If the increase in system volume causes the coolant level to drop below that of the heater core, your heater will blow cold air.