No heat in the cab, burr

[Foehammer]

Hey guys, new problem today. I got up this morning and started up the truck, and let her warm up, but after letting her warmup, I have no heat in the cab, just cold air blowing. I dont see any water leaking under the passenger side dash, and my Temp gauge shows it is running normal, no overheating, btw its like about 20* at night and about 55-60* during the day. Normally I don't use the heat but I had to leave early this morning and noticed it.

 

[3bals]

I had that happen to my dually last year. I replaced the T stats, flushed the cooling system and replaced the orange coolant with the good ol green. All is well now.

 

[chevyCowboy]

i would definetly try flushing the heater core it sounds like it is pluged up have had this happen to a truck i had and also to my moms 04 impala, i would flush the whole cooling system if it hasnt been done in a while. The intlet side to the heater core attaches to the coolant cross over, and the return line attaches to the radiator, the second hose down below the cap. just a tip the heater line attaches to the coolant crossover with a quick disconect into the part that threads into the crossover they can be a real PITA to get apart.

 

[Acesneights1]

If it's the truck in your sig (94) you MUST have a GM FACTORY AC DELCO thermostat or you will get squat for heat.

 

[Edzzed]

If you have fail safe t-stats then it could be the problem. When they fail, they do so in the open position unlike t-stats from years ago that would fail in the closed position. Manufacturers then decided it'd be best if they failed in the open position otherwise the engine over heats. This way the engine under heats or runs cool. If one t-stat is bad it will stay open and it is particularly noticeable in winter when trying to get heat in the cab. In summer cooling would not be a problem. been there done that. With my truck in the winter it took quite a few miles before the engine would shift into o/d. Which begs the next question. How long does it take to get to normal operating temp. Ed

 

[Acesneights1]

If it is not a GM T stat even if you have operating temp the coolant will bypass the heater core. I just fixed the same problem for someone with a 94. He thought I was nuts until we did it and he got heat again.

 

[Foehammer]

Ah ok thanks Aces, I have the single T-stat setup, and I just replaced my T-stat with a new 195* one from Autozone, I will have to try and find a GM OEM T-stat, any suggestions on where to get one for a good price? Do you happen to know the part# for the '94 GM T-stat? I also will flush my heater core, as I am pretty sure I need to do that.

 

[Acesneights1]

I beleive the part # is in the stickys but just go to your friendly neighborhood Chevy Stealer...

 

[Brooklyn Tow]

or find a mom and pop parts store that carries AC Delco.....Seems more and more are stocking GM parts.