2001 Blazer Help Needed

GrandmaLS

GrandmaLS

Club Member
No heat is coming out under normal operation. All the blower and control settings (Vent, Floor, Defrost, etc) work properly. The truck was a bit low on coolant but it was topped off and changed nothing. The Blazer is only heating up to 150-160, even after a long drive. Heat does start to come out with excessive acceleration but stops shortly after you slow down.

Any ideas?
 
Try bleeding the system.

Also, are both hoses for the heater core the same temp when at operating temp?

Get under the dash, and see if the door is opening and shutting when you adjust the temp.
 
where did my post go?


I posted before larry



and yes, check heater hose temp, they should both be hot, and within ~ 10 degrees of each other if you can measure them


its likely either air in the core, or a partially clogged core
 
Is there a bleeder screw like on the thermostat housing or something? I haven't seen the truck yet. I'm diagnosing from over the phone. Sorry...
 
GrandmaLS said:
Is there a bleeder screw like on the thermostat housing or something? I haven't seen the truck yet. I'm diagnosing from over the phone. Sorry...
Click to expand...

no, you will need to remove the cap(engine cold/cool), start the engine and let it warm up, add coolant if needed, then, when it is warmed up(top rad hot will be hot), rev the engine up to ~1500rpm or so and see if you then have hot heat, is yes, let it idle again and see if you need to add more coolant, add if needed, rev up once more, top off and put the cap on, see if the heat stays


honestly, I would let it cool down some, flush the core with a garden hose and compressed air, then do the bleed
 
If a flush is needed, here is a little help.

F88DF822C01D4CC7B2CA81A3F6236B1A.jpg
 
who ever designed a heater core with the inlets on the bottom should be SHOT.
HAHA I told one of the engineers that. I didn't know it was his part at the time though
 
I haven't been able to remove the rear hvac out of a Flex without taking a bath yet. HEHE we tie towels around our arms so the coolant doesn't make it to our armpits.
 
purge the sytem like dave said and id also change the thermostat, and while your there, change the radiator cap.. the $12 bucks is worth it.


then you'll have a minty cooling sytem...that trucks hould be running 195* (if it has a stock t-stat)
 
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