Mechanics

CHEVY HEATER NOT BLOWING HEAT

1989 Chevrolet Truck

Heater problem
1989 Chevy Truck V8 Four Wheel Drive Automatic

I've changed out my heater core and thermostat in the truck, fan blows hi but no heat, checked hoses coming from core both are still cold, their is no valve, one of my hoses comes from heater core to engine the other from the heater core to the radiator, i've looked on the water pump to see if there could be a connection for that hose but their is not, any help would be appreciated, I would like to get my heater workin.
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Azmadman
December 27, 2009.




Hello -

To better assist you please tell me your specific model, is it a C1500, C2500, K3500 etc and what is the engine size in liter.

Thank you very much for the donation

Have a very Merry Christmas and a safe New Year

Please let us know if what the final fix was for your car so we can better assist others. Thanks!

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ImpalaSS
Dec 27, 2009.
Its a 1989 k1500, with a 1995 5.7L engine in it, with a digital heater/ac unit, i've even checked the actuator and the blend door-they are operating, changed out the thermostat and the heater core, I have one heater core hose coming off the right side of the heater core going to the engine and the left hose going to the radiator, both hoses are cold to the feel with the engine running and the heater on high, i've filled the coolant level up, but dont get any heat with the controls on high. Ive also checked for a valve in the dash and in the engine compartment and I do not find one. I would like to get the heater working.

Tiny
Azmadman
Dec 27, 2009.
Hello -

Thanks for the info.

Is the vehicle reaching normal operating temperature on the dash gauge?

You do have plenty of coolant.(Just asking so we are on the same page)

Why did you change the core?

Most likely based on what you are saying there is either air in the system or your water pump is not circulating very well, but that would also affect the temp of the vehicle.

Try disconnecting the return heater hose slightly to release any air in the core.

Some have had to back flush the core to get the air out.

Please let me know about the operating temp of the vehicle.

Thank you very much for the donation

Have a very Merry Christmas and a safe New Year

Please let us know if what the final fix was for your car so we can better assist others. Thanks!

Find a car repair manual for your car repair questions.

ImpalaSS
Dec 27, 2009.
OK, well I changed the core out because I didnt think it was working, thats what I originally thought the problem was since its an older vehicle, i've back flushed the heater core. I bought new thermostats but the vehicle overheated with the 195f stats in it, so I put the older one its a 180f thermostat and the truck doesnt overheat, but im not sure if its actually reaching proper temp with this thermostat in.

Tiny
Azmadman
Dec 27, 2009.
Hello -

Thanks for the info

Well, that doesn't mean it wasn't bad. You are correct on older vehicles that is usually the problem. One way to check is to feel both heater hoses. If one is hot and the other not then no coolant through the core. Thus core plugged.

If there was no heat at all and the temp gauge was reading really low, then possibly a thermostat stuck open.

How many miles on the vehicle?

It may be the water pump or the radiator. If there is not good circulation through the radiator then that can cause the overheat too.

Now, I still think you have air in the system if the vehicle is reaching operating temp.

Thank you very much for the donation

Have a very Merry Christmas and a safe New Year

Please let us know if what the final fix was for your car so we can better assist others. Thanks!

Find a car repair manual for your car repair questions.
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ImpalaSS
Dec 27, 2009.
Milage is like 195000, I flushed out the radiator, temp on guage only comes up slightly-not much movement on temperature guage. Even when driving it. I've opened radiator cap with heat on high and topped off, doesnt seem to be air in system.
Brand new heater core, only overheats with new thermostat in, which is a 195f thermostat, thats why I put the old one back in -its a 180f thermostat and it doesnt seem to overheat with it in.

Tiny
Azmadman
Dec 27, 2009.
Hello -

Did you try opening the return heater hose from the core to see if any coolant was coming out? Again, if your temp is coming up. Then the heater hoses should feel the same as the upper and lower radiator hoses.

Also, I have had several gain in temperature and I had to keep shutting off, bleeding a little, adding a little, sitting the vehicle on a slope etc then finally the temp stabilized and then finally got good heat to the core.

Thank you very much for the donation

Have a very Merry Christmas and a safe New Year

Please let us know if what the final fix was for your car so we can better assist others. Thanks!

Find a car repair manual for your car repair questions.

ImpalaSS
Dec 27, 2009.
How do I check my water pump to make sure its working properly?

Tiny
Azmadman
Dec 27, 2009.
Hello -

Below is what you can check.

Park your car overnight and make sure the pavement underneath is dry. In the morning if the pavement is wet with liquid, you could have a water pump leak.

Grab opposite ends of the water pump pulley and check for " play" (looseness): Try to rock it back and forth. There should be no give. If there is, the bearings are going and it's time to replace the water pump. By the time you can feel play in the water pump pulley, you may also be able to hear the bad bearing when the engine is running - there may be a low-pitched grinding noise coming from the water pump pulley.

Visually check the water pump behind the pulley for signs of a coolant leak. If the water pump gasket is leaking, it must be replaced.

Also vehicles can overheat and or not cool properly.

Now at that.I don't see that is your problem. The engine temp is okay. It is the heater which leads me back to air in the system.

Have you found anything since our last chat?

Thank you very much for the donation

We hope you had a very Merry Christmas and have a safe New Year

Please let us know if what the final fix was for your car so we can better assist others. Thanks!

Find a car repair manual for your car repair questions.

ImpalaSS
Dec 28, 2009.
Well I had one of the heater hoses in the wrong place, I had it on the radiator and it was suppose to hook up to the water pump, the water pump had a fitting plug in the top of it and had to be replaced with a hose fitting which I did, but after connecting the hose back up and filling the system with coolant, I checked for air in the system, after filling system more and loosening hoses to expel air, I still do not get hot air from the heater, im beginning to think it is the water pump because both heater core hoses are still cold and I just put in a brand new heater core.
The vehicle will not overheat with a 180f thermostat in it, but did seem to before with a 195f thermostat, Do you think it could be the water pump, there's no play in the pulleys and no grinding of berrings?

Tiny
Azmadman
Dec 29, 2009.

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