02 Galant clicking under dash when on cold all the way

[02_8thGen_ES]

I recently developed this problem when one day I changed the air mixture from all the way hot to all the way cold. It started to click real bad so I just turned it a little towards hot it stopped. I checked under the dash and it seems the valve to let the hot water in the heater core keeps clicking after it moves fully closed. It does it 90% of the time, mostly when the car is not warmed up. What could be the problem?

[mechanic]

Sounds like the gears in the motor are stripped or something is causing a restriction thats stopping the valve from fully closing. You may have to replace the motor if the gears are stripped. Try to disconnect the motor from the lever and make sure the lever moves freely. I can post a picture of the part if you need it.

[RedGalant2k1]

Its called the water shut valve, its a common problem on our cars. I leave mine slightly on the warm side, and open my windows if necessary.