2000 Silverado Heat Problem

silveradope · January 25, 2008

About a week ago i was headed to maine in -5 degree weather and could not get any heat in the truck. the water temp was 190 the entire time. on the way home i tried the heat again and it still didn't work.

when i got home i changed the thermostat and the antifreeze(dexcool).

the temps outside are now warmer around 30-35 and i am getting heat, but not good heat.

I notice that when i am driving around town i get warm air with the fan on 1 or 2. If i turn the fan to 3 or 4 you can actually feel the air get cooler. Also when you come to a stop light you can feel the air get cooler while you are stopped. Once you start to move then it gets warm again. I checked the lines going into the heater core and found that the inside hose (closest to the motor) is very hot going into the heater core. the outside hose (cosest to the passenger side fender) is cold.

is it possible that a plugged heater core is my problem? the truck had 80000 miles on the original antifreeze(dexcool) before i changed it.

If this is my issue how do you go about flushing the heater core? Are there chemicals involved or just run a garden hose through it?

Any help would be greatly appreciated

Thanks Steven

bobcat5544 · January 25, 2008

Your heater core is pluged.

You can try to back flush it, you will need to pump water into the hose that was cold to back flush it. Do not use to much water pressure or you will crack the heater core open. you can try a radiator cleaner but it is hard to get it inside the heater core.

norsemanberg · January 25, 2008

it depends on how the coolant that you drained out looked, if it looked good you could also have a problem with a door in the HVAC system that isn't actuating correctly

bobcat5544 · January 25, 2008

it depends on how the coolant that you drained out looked, if it looked good you could also have a problem with a door in the HVAC system that isn't actuating correctly

Thats not posible is his case. Even with and bad blend door both in let and out leas hoses will be hot/warm not hot/cold

silveradope · January 28, 2008

Thank you very much.

The blend door issue was what i was trying to eliminate as an issue. i did not know if the hoses would be hot if the blend door actuator was broken.

looks like i will try flushing the radiator.

silveradope · January 28, 2008

Ok so i just finished flushing out the heater core and i honestly didn't see any restriction or notice any type of flow difference. either way i ran water through it. it seemed to flow free.

i hooked it all back up topped off the antifreeze and started it up. now i have great heat!!

it seems too easy and i am bothered that i didnt see or notice any type of restriction.

anyone have any idea what it takes to plug one of these things???

is it just a tiny piece of debris? or a whole big chunk needed to restrict flow.

i am happy i have heat. i live in newengland and need it bad but i am afraid i have not resolved my issue and it will come back when i am far away and it is real cold out.

Thanks

Steven

bobcat5544 · January 28, 2008

Small amount of debris can clog it up.

ZZ327 · January 29, 2008

might want to check out your cabin air filter too

silveradope · January 29, 2008

Went all day today with HOT heat.

thank you to everyone that posted!!!

gkh7890 · April 15, 2008

Went all day today with HOT heat.
thank you to everyone that posted!!!

Did you ever have any "slurping" (like slurping on a straw) noise coming from the heater core area? I'm having the same problem and I've noticed that typing noise and now I have no heat.

How is it running now....still good heat?

Thanks!