WHICH HOLES DO I USE TO FLUSH HEATER CORECHANGED...
2007 Chevrolet Uplander
Which holes do I use to flush heater core
changed thermostat still no heat
Thursday, November 29th, 2012 AT 7:00 PM
Before flushing and with engine at normal operating temp. Check both heater hoses to see if they are hot---they should be. If one is hot and the other is not, suspect a clogged heater core.
Post results and let me know if more assistance is needed.
Disconnect both heater core hoses at the firewall. Use a water hose to run water (at a high rate of speed) through the heater core. Doesn't matter which hose you use as the inlet or outlet during flusing. I usually flush through both hoses (one at a time).