97 Blazer 4.3l very little heat

[gbsean]

heater only blows warm air could the themostat be open all the time engine does not get above 160-170 degrees ..... also has been very cold in northeast.... radiator is full over flow is full when hot... coolant is flowing

[JHZR2]

Sounds like the heater core or hoes could be plugged, or else the thermostat could very well be busted. The thing is, in my 98 reg cab pickup, halfway on the heat dial makes REALLY hot air, at the stock 190 or so. So I dont think that on full blast, the air should only be warm, if te temp is getting up to 160-170.

 

Have you ever added green coolant to the dex cool? Have you flushed your dex-cool regularly? Sometimes a sludge can form if the dex cool is left in there the 5 years that supposedly it can last, or if the green stuff is added to the dex.

 

Are you sure there is no air trapped in the system?

 

Id suggest taking it to a dealer or someone who will power flush the system and then reinstall the correct coolant. That ought to help, and if not, at least youre taking care of some scheduled maint.

 

JMH

[mjohn]

I would replace the Thermostat...

With 180-195 degree...and you can flush the heater core yourself with a garden hose is you wish...may want to do in a warm garage...I hear the weather has been cold in the NW...Best Wishes...

[Hecktorx]

Check the radiator cap too. That can cause that problem as well.

 

Kenny

[gbsean]

I flushed the system replaced the thermostat replaced the dexcool it worked fine for 2 days then it started again ... thermostat is working temp goes up to 210 then back down to 170-180 up again then down again so themostat is opening and closing. Of course after flushing discovered a leak from water pump.... one thing always leads to another. Too cold to do it in garage going to pay to fix it. thanks for all the help

[gbsean]

did not think about radiator cap good idea but I have to fix the leak

[cmoore74]

I have had two vehicles with this symptom (2000 Blazer and a 2000 S-10, both with the 4.3L). Both were due to a clogged heater core and both clogged between 80k-90k miles.

 

A chemical flush of the system cured them both.

 

Based on this experience I will never let Dexcool go to the 100k miles GM claims you can run it to.

[cmoore74]

OK, so apparently the flush (just had it done) and new thermostat did not fix the problem in the wife's Blazer.

 

It's having the exact same symptoms:

 

- Luke Warm Heat

- Thermostat only gets up to about 170 'ish

 

gbsean, did you get the problem fixed? If so, could you please share the fix?

 

I'm really stumped on this because other than a stuck thermostat what else could possibly cause engine coolant temps to be low? I don't think it's the temperature reading because the luke warm heat would not be a symptom if it was just a bum temperature gage.

[HyperBuzzin]

gbsean, did you get the problem fixed? If so, could you please share the fix?

He hasn't posted here in over a year, so I don't think you will get a response from him.

[ryank1]

Some times a flush is not enough and you have to remove the hoses from the heater core and backflush the heater core

[cmoore74]

OK, so I had the dealership perform a reverse chemical flush of the heater core. I also replaced the thermostat, the water pump, and the fan clutch (usually only good to about 100k anyhow).

 

The problem is still there.

 

Could the heater core be totaly clogged? I'm confused as to why this would cause the engine temperature to be running around 160 deg. I would think the dealership would have confirmed the heater core was flowing as part of the flush procedure.

 

What would cause both of these symptoms?

 

Please help.

 

Thanks,

Chris

[00jimmysle]

Back flush the entire system. I had the same issue. It turns out, the passages in the heater core are the first to clog. Use a system, and isolate the backflush directly to the heater core. It worked for me. When finished, use recommended fluids.

[Padlin]

heater only blows warm air could the themostat be open all the time engine does not get above 160-170 degrees ..... also has been very cold in northeast.... radiator is full over flow is full when hot... coolant is flowing

[White00s10]

i had the same problem, i took both hoses off the pump going into the firewall for the heater core, filled it with a mixture of hot water and vinegar plugged one hose and with an air nozzle pushed about 10-15PSI into the heater core for 1 sec every 2 seconds. the sludge and s**t that came out.. goddamn. YOU have to force that sludge out of there cuz 99% of the time the dexcools gonna get it packed