2005 Citroen C5 Cooling Problem

[antduggan2008]

Hi i have a 2005 citroen c5 1.8 petrol with a coolant problem the header tank has no pressure in it after being driven and the water is only slightly warm also replaced thermostat, pipe from there to rad is hot but the one beneath isn't but the temperature gauge is reading normal (middle) and also have an issue where there is only slightly warm air coming through the vents unsure if this is linked, could the cooling system need bleeding if so how? can anyone help????

 

[paul.h]

Welcome to the forum.

 

I have deleted your similar post on the temperature topic so any replies are all in one place, plus your problem is probably better to be a separate topic. I have also removed the same post from your profile feed.

 

First thoughts are the thermostat is opening at too low a temperature - petrol should be 89°C (diesel 83°C) or there is a coolant leak. The top radiator hose should not start to get warm until the temperature gauge is near normal but if you had a code reader that gives live data you could see what the coolant sensor is giving. The radiator bottom hose should be colder than the top one.

 

If there is no pressure in the expansion tank when the coolant is hot, have you checked for any leaks and if the coolant level has fallen. Also check the tank cap is on tight but it seals by an O-ring on the cap inside the tank neck. Possible leak points include a split in the tank, a hose connection, the water pump, the radiator, the heater matrix (in this case you may get a coolant smell in the cabin), the air bleed points/caps, a leaking head gasket (check the oil is not contaminated or there is not an excess of steam from the exhaust), a leaking engine block core plug, a crack in the engine block if the anti freeze strength is not high enough to prevent freezing.

 

Did you have the same problems before replacing the thermostat, just in case the new one is faulty which would easily explain the cabin heater not giving hot air ? When you replaced the thermostat did you drain the coolant out ? The Haynes manual shows air bleed points on top of the radiator, an elbow on a heater hose next to the brake servo, on the top heater hose, on top of the box (Haynes call it coolant junction) at the gearbox end of the cylinder head.

 

For the cabin heater not giving hot air, are the hoses to the matrix getting hot - if not then there may be an air lock in the hoses/matrix which could be removed by opening the bleed cap(s) on the hose(s) or it could be the thermostat is opening at too low a temperature (Haynes gives 89°C for the petrol engines and 83°C for diesel). If they are getting hot, then the warm air flap may not be moving - if you have manual air con this may be a cable problem or if climate control could be a flap motor or the flap spindle problem. Also make sure the air con is not running but this should be automatically prevented when below about 6°C anyway.