Chevrolet Repair: no heat, heater hoses, heater cores

Question
Heater performance slowly dwindled this spring.
I replaced thermostat even though heat gauge was showing right temp.
Still no heat, larger heater hose gets warm small hose stays cool.
2001 S-10 70,000 miles 4.3 motor 4X4

Answer
Hi Dave, What happened is the coolant is dirty and plugged the heater core. To clean this out you need to remove both heater hoses from the engine and not the core. Now run water through the hose that came off near the water and then through the other. Do this back and forth to remove the dirt. Now you need to flush the cooling system really good, you can't flush it too much. I have seen the heater cores plug right back up if you don't do a good job flushing.

Hope this helps

Have a Great Day                Mark