2000 Silverado - Heater Issue

[GMC-AT]

2000 Silverado   - have an issue with heater.  It seems to work pretty "decent" most the time, but never has seemed really hot like my other trucks. Then today it went to cold... I played around with the climate temp turn knob...no change. Turned off the HVAC for a few min while driving.. then turned back on and had decent heat for a little while.  Some notes.. 

1. I felt the heater hoses... the one closest the engine is hot...I can barley hold my hand to it.   The other hose is warm but not hot. 

2. Truck warms up to 195 as normal

3. The blend door is working fine.. it switches from floor, defrost, etc, etc just like it should

4. Nothing has changed on the truck as for new parts, etc..

 

[richard wysong]

the hoses being different temps means the heater core is partially clogged. remove the hoses and reverse flush it with a garden hose. Either Lisle or KD make a heater flushing tool that allows you to give a blast of compressed air along with the water, I added a water shut off valve to mine to save trips to the spigot