i have a 89 mercury grand marquis 302 8cy. when the temp. is above 30 or so heat is fine, anything below this not cold, but cool.when i first bought the car 8yrs ago when winter came it showed up. the only owner that had it before me put in a new heater core(i saw it & it was new), also new radiator, and thermostat (hot one) still no luck. my mechanic checked water temp. o.k. checked water hoses all running with proper heat feel o.k… brother-in law took off dash checked door opening and closing perfect.i don"t know what else is left. the previous owner left all repairs paperwork. brought it in for no heat. they changed the thermostat. this must be one of those cars that for no reason no matter what is done---- it is what it is thanks guys. i hate to sell it this way
What is the engine temperature when the weather is that cold? It could be that the engine is not getting warm enough to put out any heat. Some people block off a portion of the radiator with a piece of cardboard order to cut the airflow through it. If you decide to try it, do not block more than half, the lower half, and be sure to remove it when winter is over.
thanks for the reply, i wish i had a gage to look at but this car does not have one?? i also blocked the radiator but still nothing. that really kind of confused me.i know that it was working because one day a couple of weeks ago the temp. here went to almost 70, ( i thought i moved south for a day) went to play golf, and forgot to remove cardboard, thank god it started to boil over when i got to the golf course. i removed the cardboard after golf and put some antifreeze in. it won"t boil over on cold days but still no heat.i"m stuck??