If I run the A/C the temp gauge shows normal, but it was a cold morning today and I cranked on the heater and it only blew lukewarm air and the gauge never went above C.

Any ideas?

 

replace your thermostat and flush your coolant, I also highly recommend spending the extra money and getting the t-stat from Nissan

 

Could be air in the system. When was your cooling system last flushed & filled? If not recently, I would also suggest doing what KRRZ350 stated above ^^^.

 

Your thermostats probably stuck open.

 

change your thermostat and fluids and dont expect to get hot air when you first start the car in the morning or after its been sitting for a while

 

Why has nobody mentioned your heater core???

 

because the engine temp was low as well as the heat blowing out.

 

I have been in a Chevy Cobalt that blew hot air long before the TEMP registered much above C. I missed, however, your statement that the needle did not rise above C. I agree with other: thermostat.

 

when I had my 95 Max it did the same exat thing- I replaced the t-stat and cooland and it was good to go

-Matt

 

rember also...your car does not run properly at anything below operating temperature. Although damage probably won't occur, running rich(what the car does when below normal) can foul plugs and sensors long term...not to mention decreased fuel mileage.

 

running it colder than optimal can also lead to increased engine wear...

-Matt

 

^^^Correct. During intitial startup temps, most vehicle run 40% +/- rich. Can eat some SERIOUS fuel..and prob cause some decent dmg. FIX IT!