Ok I just bought a 1991 Maxima SE... I love the car. The thing is it is cold in chicago, and the temperature always stays cold on the temp gauge unless i turn off the heat for a while. If the heat is on, it blows cold. After the car finally heats up, ill turn the heat on and it will blow hot, then the car will get cold again and start blowing cool air. What could be the problem?

Thanks,

Matt

 

1. make sure your coolant is full

if that doesnt work

2. flush your heater core

if that doesnt work

3. replace your Thermostat

it sounds like your Thermostat from what you describe.

 

If the temperature gauge goes up and down instead of remaining steady, I doubt if flushing the heater core is needed. If the coolant level is full, then the thermostat has gone crazy. I'd replace the thermostat anyway because they only last a couple of years and who knows when it was last replaced.

And when you replace a thermostat on these cars, you have to bleed the air out of the heater core. See the "stickies" at the beginning of this forum.

 

My car wouldnt get warm, and i replaced the thermostat which was pretty easy and inexpensive and it fixed it right up.