2003 Mitsubishi Galant No Heat

2003 MITSUBISHI
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DISCIPLETOO
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  • 1 POST
2003 Mitsubishi Galant 60000 miles

Thermostat is a couple of months old. When I turned from cold to heat last week, I got a sound like the fan was clicking and the heat started working. A couple of days later, no heat. I checked the hoses and fuses, and after messing around with the hoses the heat started working. Now no heat at all. Supply hose gets warm right by the control valve but not by heater core and return stays cool. I'm thinking either a sticking control valve or a clogged heater core. The control valve is pretty hard to get at and I'm wondering how to check it. Any help is greatly appreciated.
Apr 14, 2006 at 10:28 PM
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LOSONE
  • ✓Experienced Mechanic
  • 1,616 POSTS
Get the engine warm check heat on the engine side of the heater hose then check for the same heat on the other side of the heat valve. If it is not the same then the valve isn't opeating. This could be a bad valve or a problem with the control. system. It is most often the heater valve.

If the system doesn't have a heater valve (usually in the engine compartment with a heater hose on both sides) then it is probably a blend door problem. Good luck
Apr 15, 2006 at 1:46 AM
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Suggested Repair

With the engine warm, compare temperature on the engine side of the heater hose and on the other side of the heater control valve. If the temperatures differ, the valve is not opening—most often a bad heater valve, or less often a control-system problem. If the vehicle has no heater valve, suspect a blend door problem.

Conversation Summary

The owner of a 2003 Mitsubishi Galant with about 60,000 miles reports no cabin heat after intermittent operation. The thermostat is only a few months old. The supply hose gets warm near the control valve but not at the heater core, and the return stays cool. The expert advises comparing heat on both sides of the heater valve with the engine warm. Unequal heat means the valve is not operating, usually a bad valve or a control issue. If there is no heater valve, a blend door problem is more likely.

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