Ford mondeo overheating

[rebman01]

I have a 12 plate Mondeo titanium x, 2 L diesel when towing my caravan after a few miles the temperature gauge shoots up to red resulting in loss of power and having to pull over to turn off the engine and cool down. Last time I decided to turn the heaters on full and open the windows, the car then pulled like a dream with no issues, this only happens when towing. Any ideas. T.i.a

[finlo]

Are the fans kicking in?

[rebman01]

Yes when the heating is on

[finlo]

What about the radiator fans?

[xjay1337]

Sounds like an air lock or thermostat issue.