Hello.

I have a Citreon C3 1300. It overheats when engine under pressure. Normal driving the car is fine. I have took the thermostat out. Does anyone think the radiator or the water pump is at fault. When the car overheats if i drive with heater on full, the temp goes back to normal.

Bill, October 2011

If the radiator is blocked Bill, and a flush doesn't work, then you may have to bite the bullet and buy a new radiator.

Good luck.

ChicksFan, October 2011

Hi ChicksFan.

Thanks for your help and advice. I will check all you say, there is a hell of a lot of lime in the water here, so maybe rad flush would help.

Bill.

Bill, October 2011

Has taking the thermostat out cured it? If so then it sounds as if the thermostat was sticking closed and a new thermostat should cure it.

If not, how long has the coolant been in? Has it ever been renewed. Draining, flushing and renewing the coolant may well solve the problem.

Does the radiator get hot all over when the engine overheats? If not, then the water pump could be at fault if the vanes have corroded - if so a new water pump would be the answer. Or there could be blockages within the radiator. Try flushing the radiator with a reverse flow of water using a hose. That may clear a build up of sediment.

Is the cooling fan cutting in when the engine gets hot? It could be the fan itself at fault if it is not cutting in. Test it by putting a 12v supply directly to it. If it doesn't turn then replace the fan.

If not the fan itself, then a faulty temperature sensor may be the culprit, or a thermostatically controlled fan switch may have failed. The latter usually screws into the radiator on most cars. You can test it by undoing the plug and bridging the contacts in the connector with the ignition on. The fan should come on while the contacts are bridged. MIND YOUR HANDS THOUGH, KEEP THEM AWAY FROM THE FAN - YOU DON'T WANT TO LOSE ANY FINGERS!

ChicksFan, October 2011