Mitsubishi Repair: no flow to heater core, core assembly, heater core

Question
I have a 2002 Galant DE. The engine heats up properly but the vents do not blow hot air. My mechanic tried to get flow to the core but had no luck. Last season you could get heat by turning the thermostat on the dash back and forth several times. After making a odd noise the heat would come. The mechanic verified that the switch was opening and closing but now he is at a loss. Any ideas?  Thanks!! Bob

Answer
Bob,
There can be a couple reasons for you not feeling hot air.  I would first suspect that the solenoid that allows hot coolant to flow into the heater core is not openning properly.  A year ago when you would have to move the thermostat back and forth several times to make it work is an indication there is a problem with the solenoid receiving a signal from the switch to open the core for coolant.  The switch may be fine, but the problem lies in the heater core assembly itself.  Another possible scenario is that you have a damper door that is stuck open.  This damper door allows fresh air to come into your cabin, and if its stuck open, you may not feel warm air coming out of your vents.  But the more likely cause is a stuck solenoid in your heater core.  Unless your mechanic has done so, he should remove and inspect the heater core assembly and check all the eletrical and hose connections.  Removing the core is time consuming, so get an estimate in price first before you have it done.
Good luck!