I've just had a bit of a saga with my 05 50k 1.3 duratec Ka cooling system and thought a few of my experiences might be useful to someone with this car.

First problem was a split header tank which is a regular problem leading to lost coolant and overheating. Fixed it and thena few months later overheating again in a major way. system ran out of coolant and light came on.

Found the plastic thermostat manifold on the right side was cooked and had broken letting rapid loss of coolant. Replaced it (£40) and then re-filled and ran engine all seemed ok but then found overheating causing the fan to come on even though hoses to radiator were cool. Took out thermoistat to check is was working ok and it was so moved on to considering lack of circulation was down to the water pump which was squealing a bit but not leaking.

Bought a pump (£22) and fitted it from the underside with only 2 inch working clearance and got belt back on which needs a long ring spanner on the pulley tensioner wheel and then pull the tensioner wheel toward the back of the engine while you pull the belt onto the main wheel at the end of the crank. Old pump was ok even though it had a plastic impellor - replacement pump had a metal impellor.

So circulation wasn't the issue. I returned to the thermostat to check the new plastic manifold - discovered new manifold had no hole in the breather pipe connection so the sysem was creating a massive airlock preventing circulation and cooling - new rule - always check replacement parts even when of a well known make.

Also during all of this the heater control switch crumbled due to the high temperatures it was working under - easy job to replace (£15) after pulling plastic bulhead covers out of the way. A clear breather and tube is essential to filling the system so always check it is clear even when the manifold is new. The plastic parts used in these locations have a limited life and the cost of them is very small compared with the cost of a siesed engine or cracked head - a case of designing down to a price rather than up to a standard.

Also this car has a warning light for overheating, however it means that the car can end up operating at a high temperature when there is a problem and the driver is unaware until the system finally runs out of coolant and the light comes on. Otherwise the car works well but looking after the cooling system should be a heads up for all owners. I hope this was useful if you have been having problems with your Ka.

(Edit - moved to Technical and some paras put in to avoid readers losing the will to live.)

Edited by Avant on 29/12/2013 at 19:53