405 heater mystery

[405stdt]

Hi all,

Just wondering if anyone can shed some light on my heater problem. In the warm weather I have been setting my heater from hot to cold, but every so often I get a blast of hot air through the vents, then it goes cold again. What could be causing this?
The coolant level is fine and there are no leaks inside or outside the car.

[Dave45]

Sounds like a faulty heater control valve (the unit the temp control cable connects to)

Probably got a weak spring and seal. Just replace it and bleed up the system.

[405stdt]

Ok i will check that. Is it under the dashboard in the passneger footwell?