Gents:

cabin heater works fine down to about zero, then quits below that. Put car in heated garage for a few hours and drove it in the cold and all is well. Cold soaked overnight and problem is back.

Ideas?

northwoods ( of minn)

 

Check whether the coolant level in the radiator and/or reservoir is low -- top off if necessary. Is the coolant freezing solid in the radiator?

 

if the coolant is freezing you might not be adding enough or adding too much. It has to be within 40-60 % of coolant.

 

when it is below zero where i am at the heater usually blows out cold air everytime i start moving at all, my engine can warm up if i'm at a stop, thought usually i don't stop long enough for it, but when i start moving the cold air cools my radiator too quick and the temp gauge on my dash starts dropping, so it might just be that it's too cold also.

and i used premixed fluid so i know that it's not actually freezing

 

I would guess that your coolant mixture is a little off and it may be freezing up at the heater core.

If you are not getting enough heat when you are moving, your thermostat maybe sticking a bit (open) and letting the coolant seep through the radiator.

 

no matter how cold it is outside, the engine temperature will reach the middle position unless we are talking north or south pole temperatures. the car should warm up and thus warm up the coolant to its operating temperature. so I don't think your theory holds. I would consider the suggestion about your thermostat being stuck open. it is supposedly an affordable and relatively easy fix.