Mk3 heater temperature control

[1 gti]

My temperature control is stuck on hot!! Not good when it's 20c, lol. Fan speed and direction still works normal. Taken the unit out and the temperature wheel just turns but cables don't move. What's the possible causes? Cable come off on the flap end? Any help would be appreciated. Cheers

[Wayne]

I guess the cable has come off, cannot see it being much else.

Is the engine temp all ok.

[1 gti]

Engine temp doesn't go past 70. Doesn't over heat or anything though. That's most prob temperature sensor

[thai-wronghorse]

Sounds like you need a thermostat for starters as the temp gauge should sit at 90 once the engine is warmed up.

[1 gti]

Thermostat? That's the temperature sensor right?

[thai-wronghorse]

No, its a temperature sensitive valve that sits beneath a plastic housing on the side of the water pump.

[javalin]

No seperate bits, temp sensor does what it says, and thermostat regulates the engine water temp to 90c by directing coolant out to the radiator as needed.

If it comes up to 90c when standing, then thermostat needed.

[1 gti]

Doesn't over heat. When driving and ticking over it stays at 70 and no higher. Going to change thermostat and see what happens. I think it's heavy on diesel too

[thai-wronghorse]

Engines generally overfuel when they don't reach optimum running temperatures as they over compensate with open chokes, cold start valves etc.

[1 gti]

Hope the thermostat is at fault then