My car warms up very slowly and never gets hot inside like it used to. Both of the ac/heat cluster lights are out and the temperature gauge always leans towards the cold side. Also, after a quick scan concerning my check engine light, the code had something to do with a thermostat.
My heat doesn't get as hot as it used to. on 2005 Buick Century
by mdubose22 in Cincinnati, OH on January 23, 2013
ANSWER by gmc4me on January 23, 2013
The thermostat may be stuck open not allowing the cooling system to get hot as it should. I would say you have a stuck open thermostate. It's a cheap fix about $30 in aftermarket parts. You will need the thermostat, thermostat gasket and a gallon of coolant 50/50 mix dexcool.