Heater not working..

[rhandwor]

A lot of shops charge $60 to $80 for a power flush. Hopefully he's stretching the pressure he uses. If its a reputable shop he will fix it if it damages your cooling system.

[bigry2004]

hmm.. okay. well, what's the maximum pressure to use without definately damaging something?

[rhandwor]

It depends on what he is doing. As an example he disconnects both radiator hoses. He has a pressure on his air compressor he probably has a fitting to hook to the air hose. He might set it at 16psi hooks up the hose to the heater hose he gets ait through it. He then disconnects it and puts a water hose on it. Say he uses 60psi shop water pressure. He will crack the valve and as the mud is flushed he will open the valve all the way. As the other end is open he is flushing with 60psi until the water runs clear but their isn't 60 psi pressure on the system. I have removed the thermostat and disconnected both radiator hoses put a hose in the top hose a foot or so and ran the water until it was clear.
Radiators I usually have a shop clean and rod them. They take the top off and have a flat rod they push through or they will sell you a new one if to bad.
If he runs a shop I'm sure he knows he is doing but I'm not sure you understand what he is doing. You would hear he blows up radiators.
My pressure tester on a closed system you check what the cap is rated at and don't try to exceed it. Say a 16psi cap over 20psi you can ruin an old radiator.

[1996blazerLT]

Before having the whole thing pressure flushed, check the temp of the input and output hoses to the heater core at the firewall. Although 150-180 may be a little low, it should be plenty to feel heat in the cabin. I suspect it may be the HVAC Heater blend door actuator, which unfortunately, is located on top of the heater core box. It's electrically driven and not vacuum actuated. I found it while changing my heater core and replacing a vacuum actuated door to the defrost outlet. You can see a good photo at rockauto.com under heat & a/c.
You may still need a flush. I had the same gunk after about six years. Cost me a radiator, heater core and auto part store flush. I think it's the Dex-cool. I changed to the green stuff.
I hope that it's not the heat-a/c blend door motor. A real pain to get to is all I'll say about it.
It could just be an electrical issue. I don't know about the fuse(s) that feed it.
good luck

[bigry2004]

Problem solved. Thanks for all the help guys. I had a radiator shop do a quick flush of the heater core. Everythings back to normal.

[BlazerLT]

I don't think your problem will be solved for long.

You better go get your coolant changed seeing it is now started to mess up. Flushing the heater core will only be temporary.

The worn out coolant will return and clog it again.

[bigry2004]

Originally Posted by BlazerLT

I don't think your problem will be solved for long.

You better go get your coolant changed seeing it is now started to mess up. Flushing the heater core will only be temporary.

The worn out coolant will return and clog it again.

Hmm. well i mentioned prior i had a new radiator installed about a month ago, and a flush and re-fill was done that. Won't that be enough?

[BlazerLT]

Originally Posted by bigry2004

Hmm. well i mentioned prior i had a new radiator installed about a month ago, and a flush and re-fill was done that. Won't that be enough?

Yes, sorry about missing that.

Better safe and say something than assume.