hi everyone..heating ???

[71C-10DAD]

Cant get any warm air in the cab. Truck can run for an hour and all i get is very luke warm air outta the floor vent and one of the dash vents the other is not blowing at all. Any ideas....

[myoldchev]

Are you low on coolant?

[wild one]

Thermostat stuck open, missing, or rusted out - how long has it been since it was replaced?

[Blue85]

factory A/C truck? If do is your heater valve stuck? If not, your heater core is likely plugged with leaves and other junk

[al's71gmc]

As far as the dash vents, sounds like some of the tubing is missing or came apart.

[cdowns]

removing the blower motor then the heater core and cleaning out the 35years of crap out of the housing will help// and inside the cab checking the diverter box to see if the cheap ass factory flapper is busted and also replacing the ductwork if needed // putting a new 190degree thermostat in // do all that and you should have plenty of heat

[Boog]

Feel the hoses going to and from the heater core. If one is hot and the other is cold there's likely an obstruction. If both are cool the thermostat may be missing or stuck open. Check under the dash for loose or missing, broken hoses and broken or disconnected cables.

[shifty]

Like everyone else said -

- Check your hoses for heat at running temp, heater core might be stuffed.
- Check your coolant level in the case your heater core is leaking.
- Check your blower (round cylinder next to fender inside engine bay) to see it blowing.
- Check all hoses inside the truck connected to the black box under the dash/radio
- There is a steel flap behind the heater core assembly, it may not be opening and closing as necessary.

I'm curious if there is a newer model vehicle's heater core and blower motor combo that would work with our trucks ....

[PanelDeland]

My heater valve would not open.The dash lever moved and everything else seemed to work but I had Mrs.P move the lever and watched for movement from the valve.It only opened about 1/8 of the way.Slightly warm air.When I manually opened it it got hot quick.

[70 shorty]

My money is on stuck open or missing thermostat. That's definitely where I'd start, it's cheap and easy to fix.

[shifty]

I would believe the thermostat was stuck open if the engine temp was not getting very high, but I didn't see where the original poster said what the temp at idle was. Cheap and easy fix is the one that doesn't cost any money - check the flapper on the firewall

[Brad]

Originally Posted by shifty

I'm curious if there is a newer model vehicle's heater core and blower motor combo that would work with our trucks ....

I think someone here has used a Cadillac blower motor that fit right in place.

[shifty]

S10 blower fits there too, from what I gather.

I'm really interested in finding something that would be a direct boltup that isn't nearly as bulky as the stock unit. I remember my mid-to-late 80's GMC S15 had the heater core inside the car, IIRC. I would love to find a similar setup for this truck. Blower on the outside, blows air inside, over the core, then whammo, hot air.

[jacobs]

In the same way minerals clog a radiator core, minerals can also clog heater cores. Backflushing a heater core will get rid of loose sediment but won't get rid of hard mineral deposits. NEVER, NEVER use tap water in a cooling system. Tap water is full of minerals. Use only distilled water.