That was at 81,744 miles.
From the invoice:
"Customer states when turn on the hear is getting cold air only. Test heater systems. Heater core restriction. Performed complete flush of cooling system."
Labor: $464.00
GM coolant $43.60
Thermostat $16.70
Cap 1.203 $13.04
Cap 1.203 $13.04
Job #1 total labor and parts: $550.38.

THEN I brought it BACK to them for the SAME problem at no cost to me, on April 20, 2007. Notes state: "Slight restriction in the heater core. Back flushed heater core."

Now I hear the sound every now and and again. I know what it is, but again, have chosen to ignore it for fear of another $550.38!

 

Ok. The details. Still does not mean that they got the heater core cleaned completely. You may want to try a stiff vinegar and hot water flush and let it sit over the weekend like that (it is supposed to be warmer for a few days). Vinegar works great at loosening up junk in heater cores!

 

Ugh! When it rains it pours! The blazer is running smooth now that I had the plugs and wires changed (misfire 5 - bad plug!),but now I have NO HEAT

I'm taking it to VIP today (I really like this one mechanic that did the engine work) and will list the items that I think it is so that way I am not paying an arm and a leg for diagnosis time.

Problem:
Blowing cold air. Temp registers normal.

Diagnosis:
Bad thermostat? (cheapest fix)
Blocked heater core? (Do a flush????)

If still no heat, then:
Check vaccuum lines - make sure no pigtail hanging free?

Have I missed anything?

Again, I have to say BIG THANKS to Kyle and his advice. I will never be scared to go to a shop again because I will always have the knowledge before!!!

 

Did the flush and got a new thermostat.

GUESS WHAT? Both hoses are hot, but the air is luke warm.

Any ideas???

 

I would do a flush anyway. It is cheap and easy enough... Even a small flow through the core can result in both hoses being of similar temperature.

The other option would be a malfunctioning blend door actuator (electronic) in the HVAC housing, but that is a bit more expensive and quite a bit more difficult to get at.

 

Do you mean a reverse flush, like this HOW-TO: Heater Core Flush ? (Awesome write-up! I would do that myself, except everything is frozen here.)

VIP did a flush. I specifically stated heater core. They didn't do a reverse flush. Do I go and request a reverse flush?

This will be my 4th trip there....

 

This is one of those things that you should probably do yourself to #1 - make sure it gets done right and #2 - see if any crap comes floating out.

 

I hear ya, but I can't...the hose is frozen outside. Might I be better to take it to a 'mom and pop' shop in our small country town, in hopes they don't rape me in labor costs?

 

Me again![&:][&:]

I ended up bringing it back to VIP and they did a 1 1/2 hour flush on the heater core (reverse flush).

It had heat and then on Monday it decided to act up and not give meheat. :-(

If I keep the heat off, the vents get hot. If I crank it to blow on high, the air iswarm, then luke warm and then cold.

Sounds like a vaccuum noise on passenger side, under glove box, when I turn off heat from high.

Both core hoses are warm., so I'm not convinced the core is blocked, again.

I'm thinking a hose might be loose?!?!?

I read some other forums....control valve? Is this something visable to the naked eye?

 

There is the blend door in the HVAC housing that controls the flow of air over the heater core, but there is no valve that prevents flow of coolant through the core.

This sounds like a restricted core, especially if you can turn off the heat for a bit, then turn it on again and have warm air coming out for a short period of time. But I suppose that it could be something wrong with the blend door actuator which is electric...