Why does my 2003 Mitsubishi galant only blow cold air from the heater vents?

Answer 1

there are 3 possibilities here. let's hope the probem is #1 or #2/

1) check for low coolant in system. if very low, you will loose circulation throughout system, particularly throug heaer core.

2) run vehicle for 10 minutes. shut off engine. pull off rd. hose from thermostat housing and check for coolant above thermostat. chck temp if present. if none or if present and cool-replace thermostat=thermostat stuck, either open or closed.

3) if coolant at proper level, the problem is most assuredly a bad heaer core-either clogged or air-locked.

**if coolant level fine and thermostat fine,I would, first, remove the rad. cap, pull off the heater hose to the block/manifold. I would get a garden hose and terry towel, start the engine, place the hose into the rad. opening, wrap with the terry towel-with pressure around it and have omeone turn on the water full force to force water/pressure through the system to get water/coolant through the heater core-if physical block and if air lock. once the coolant goes through core, you will be able to see the coolant exiting the heater hose that you just disconnected.

reconnect hoses, replace rad. cap. and rfil system wi proper mix of coolant.

a quick "solve",in most cases , is to replace the thermostat. if the thrmstat is stuck open, the coolant won't heat up enough in colder weather to offer warmt inside he vehicle. if stuck shut,the hot colant won' circulae thru the core for introducing the warmth of the heated coolant into the vehicle.

if you replace the therm. and stilll have problems, try the **suggestion above.