Renault Clio - Heating and Cooling - Over heating Problem

[Clionut]

I have a 1992 Mk1 1.2 Clio which persistently overheats.
I have flushed and cleaned the rad many times and refilled with the best antifreeze mixture I can get. The water pump is ok and the heater works fine so I assume I am getting no airlocks.
I have tested the fan and that is also fine.
I noticed today that the seal in the header tank cap is damaged.
Could this be the cause of the problem?
I assume that if the cap is faulty the coolant will boil at a lower temperature and flash to steam.
Any advice would be most appreciated.

Thanks

[harddrive]

Hi Clionut, ( Great name )
I would certainly start by getting the cooling system pressure tested ( most older type of garages can do this ) in case the head gasket is leaking and buy a new cap , making sure that it is of the correct pressure type ( on the top of most caps it will have the rating) if not car spares shops will have a catalog to tell you .
Regards harddrive

[Clionut]

Thanks
I am pretty sure that the head gasket has not gone none of the normal signs are present.
I will start with the headertank cap and see what happens.

[RenaultBreakers]

You have not mentioned if you have checked the thermostat? a very important part of the cooling system as if it is faulty will cause a over heat.
Is there steam pouring from under the bonnet or is the light coming on in the dash?

[Clionut]

Hi

Yes replaced thermostat when I last emptied and refilled coolant a couple of weeks ago.
Temp guage rises and there is steam from under bonnet. All hoses are ok so I assume it is coming from the header tank?
I am now completely flumaxed by this problem.