Mechanics

97 CHEVY S10 PICKUP

1997 Chevrolet Truck

I have a 97 Chev S10 LS, the heater is not working. It will work if the truck runs at 45 mph or faster [warmer mileage]. There is not a leak from my radiator or heating system in or outside the vehicle and i'm not losing fluid levels [unseen slow leak? No]. Looking for a diagnosis and instructions on repair.
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Joleneumentum
January 13, 2007.



I would like to help but need a little more info. What exactly be you mean by no heat. Does the fan work and if so is it hot or cold air? When running the car on the hiway is the blower on or working?Once I know this I can help. : D

Tiny
Backyardmechanic
Jan 13, 2007.
Yes the fan works. Now that I think of it. It really only works like it " used to" at the higher 2 levels [have low, low/med, med, high air intensities. Etc], but it still blows no matter what. When the car drives at lower speeds, it blows cold air, but it still blows/works.

When it's at the lower intensities, it will blow very little air, also cold or warm air depending on the speed I'm going.

Tiny
Joleneumentum
Jan 13, 2007.
The car should still give you heat even with the limited fan speeds. You can have a few possible reasons for no heat. Either the thermostat is stuck open, the heater core is clogged, or the heater control valve isn't working. Lets start with the easy one first. If the thermostat is stuck open( or has been removed) then the car would not be operating at normal temperature. Check the cars temperature gauge to see if it is in the operating range. If it is then the thermostat is good. Next is to check the heater core. With the car warmed up and the heat on feel the heater hoses. If working properly both hoses should be hot. If the inlet hose is only hot then the heater core is clogged and needs to be flushed. The last thing to check is the control valve. You need to check the hose going into it and the one going out with the car warm and the heat on. They should both be warm if not the valve is stuck closed or is not operating correctly. This valve is either operated electrically, mechanically or by vacuum. Good luck

Tiny
Backyardmechanic
Jan 13, 2007.