I noticed last night that my defroster only blows hot air for about 20 seconds and then the air completly cools off. Not air conditioned cool, just not hot at all. I bought the car used and the guy said the only mod was a 160 thermo. My temperature gauge never goes past about 1/8 of an inch past the 160 marker on the temperature gauge, even in the HOT Texas summer. Is this what is keeping my car from sustaining hot air? Or could my heater core be bad?
I plan on changing my thermostat next weekend. if it is my heater core, what all needs to be changed and how much does a heater core cost?
Thanks

 

check your passenger side floor for wetness under the carpet.. I'd try flushing the heater-core if theres no wetness, probably clogged. I have a 160 thermo and after 15mins of driving, you'd think I still had a 180 thermo...

 

i highly doubt the thermo is suspect

 

So, if there is no wetness in passenger side carpet (which I am almost positive there isn't), then flush the heater core. How do you go about doing that? Any write ups.

 

Remove the hoses and use a garden hose to flush it one direction and then the other.

 

thanks shoebox.