I have no heat on 2001 Chevrolet Blazer

The ac works fine and there is no leak in the heater core

Asked by for the 2001 Chevrolet Blazer
1 answer 7 comments
Have you ever removed that red 'crap' it came from GM with called Dex-Cool?
Yes I have replaced the Dexcool. I have heard this stuff will settle in the lowest point and solidify.
Possible stuck open thermostat, low coolant level, heater controls or restricted heater core. Replace t-stat first thing anytime there is a heating/cooling problem with the engine which also affects hvac systems.
I have done all of the recommended except replacing the core., I am about to use air pressure to blow out any clog.
If it is restricted, i have good luck with air and water together with a rig i made up. Try the air, cant hurt.
I ran water through it. It flowed fine in one direction but not the other.
I was wondering it there is some find of check valve in the system that would
prevent the flow in one direction?
Not that i am aware of. Hook hoses back up, refill rad run until hot and see if both heater hoses get hot. Post results.
I ran the motor to running temp. The big radiator hose was to
hot to touch but both the heater hoses were barely warm. I had no problem holding
Them in my hands. I held them close to the firewall.
addendum : I ran the air pressure up to 100 lbs. It blew out something,
Because I now have heat. Thanks tor the support.