2000 Envoy heater only blows cold air

[Cityboy2468]

I have a 2000 Jimmy/Envoy and my heater doesn't blow hot air. The blower is fine just need to know if it is the heater core or if it could be something-else. Any help would be appreciated.

[shawndalyn]

I am having the same problem, did you get it fixed? what was the problem?

[ecsymons]

Originally Posted by shawndalyn

I am having the same problem, did you get it fixed? what was the problem?

The GM 4.3 liter used in the mid/late 90's into the early 2000's ALL have this problem if the cooling system is not flushed every 30k miles. Corrosion builds up and clogges the heater core. I have owned a 1997 Jimmy and my friend has a 2000 envoy that we just flushed out with a "powder" cleaner drained the system, went back and flushed the heater core by disconnecting the two hoses at the ENGINE block (NOT THE HEATER CORE AS YOU WILL DAMAGE THE SEALS) and hooking up a hose to the LARGER heater hose and "BLOWING" it out with full force. Refill, and your good to go for a couple years OR 30k miles. Rinse Repeat as needed. whata pain..