Hi

My girlfriends ka has now overheated twice where the presure in the header tank builds up and the coolant steams out all over then engine. It was taken to the garage and filled up and checked for leaks and it is fine.

So far, there are no leaks in cooling system, The thermostat is opening and allowing water to the rad so all coolant pipes get hot. The pump looks to be pumping coolant around, There are no signs of the head gasket gone as no mayonaise in oil cap or header cap and no misfires.

Firstly, there was no cold air blowing out of vents when on cold. After some messing, this swapped and there was no hot air. I looked into this and replaced the heater valve as it is common to fail and now I have hot or cold on demand.

I also noticed when emptying the water from engine that there was a slight colour to the water which sugests traces of oil being in it but is this suspected being a 10 year old car of has the head gasket gone?

Any ideas?

Thanks