Engine overheat?

Hi folks - I'm a newbie to the forum having just bought a luverly 2004 C3 Desire for my daughter. I drove it over 40 miles home from where we bought it (a small dealer) without mishap but all of a sudden the water temp gauge went up to max, the red bar. It had been fine till then at two yellow bars. I turned the heater up to max to dissipate some of the heat but it didn't feel excessively hot, certainly no hotter than my Volvo is at max heater setting. There was plenty of water in the reservoir. Anyone any clues before we take it back? Why should it suddenly show max like that and do you think it really was overheating?
Thanks for any help and we look forward to being a long time forum member. Cheers, Blossom.

Welcome to the forum, blossom.

The temperature bar should be at 3 bars for normal running temperature (easily at 3 bars after 10 miles)

The colour of the coolant should be very red, it almost glows red and the level must be between the min and max marks when cold. (there is not much difference between the min and max) any deviation shows something is not right.

You can quickly test the temp sensor by switching on the ignition an allowing the temp sensor to self test the lights (look to see they all go on, then all go off) no need to start the engine as you have seen the lights come on after a run.

To me, it sounds like an air lock in the cooling system (if the coolant had been changed) (and the self test passes).
Its not advisable to drive if there is a coolant problem because you risk damaging the head gasket (warping the head).

I would call the garage and let them know what happened and hopefully they will tow/low load it to the workshop for repair.

Good luck,

Please let us know how you get on!

Thanks for the advice, C3driver52. Someone else has said that it could be an airlock. My daughter is away and the car is garaged until the weekend when we'll test it again and try to remove the airlock. The seller knows of the problem and the car will go back if we can't solve the issue. Cheers, blossom.

I too have this problem on an 04 reg desire, we bought the car 2 months back & a month ago we went on a 300 mile trip over a 3 day weekend, everything was fine until we were nearly home & the red light came on & beeping at us saying overheated, so we stopped & everything seemed fine, we waited 5 min & turned the engine on & it drove home fine this had happened 2 times since & has baffled the place we bought it, an AA mechanic & our regular good mechanic.

Hi again Peeps - our local independant Citroen garage knows of our problem with the engine overheat indicator and he is 100% convinced it is the water temp sensor which throws a wobbly every now and then. Changing the sensor would cure it apparently. It only ever happens on a very long run which the car seldom does, recently it's been OK and we keep saying,'the next time it happens, it's going in!' But the next time it happens, it's going in!
Cheers,Blossom.