heater blowing cold on my 172

[katieee]

right im hoping there is a common fault with the heating on these or this may get expensive! My 172 heating is intermittent some days it will blow out hot like it should then others it will just blow cold when on its hi setting even after hour or so of driving :/ i have checked and topped up the water but this made no differnce anybody have any other ideas?

cheers

 

[Tony Hunter]

You may be lucky and have an air lock.

Bleed screw (10mm nut) is on the thermostat housing. Give that a go first. Are you top and bottom hoses getting hot?