Story so far.  Head Gasket changed in summer due to exhaust gases pressurising coolant.  Early december radiator fan switch fails and coolant becomes pressurised again.  Renewed fan switch, coolant running into expansion tank through thin hose from thermostat housing so water pump ok.  Again took head off to replace Head gasket, took it to specialist cylinder head engineers who check it for flatness and actually found that it was flat, he skimmed it by about 2thou just in case there was any low spots after I told him the problems I had with the engine.  Thinking back to when we fitted the original gasket in the summer, torque values were as per haynes manual, resused head bolts as advised by haynes manual, think we should of cleaned the bolts and lightly oiled them which we didn't do however car was good for say 2k miles.  Also should we have reused the head bolts? I thought they were not stretch bolts?  Also would it be a good idea to clean them and used them again or get new ones?

 

Victor

The bolts are stretch bolts, and as such single use only.

Darkside do head studs. These are re-usable but very expensive, best to stick a new set of ARL bolts in.

Has the engine overheated at all since you started with the issues???

 

Its always good practice to replace the head bolts even if it says you can reuse them as they are put under alot of stress, its also a good idea to put a light coating of engine oil on them to refit as they make less noise when they get tight and you the bolts spend most of there life covered in oil and means they tighten tigher than putting them in dry (lubrication affects torque)

You need to ensure the thermostat is working correctly, including ensuring that the housing hasn't collapsed internally jamming it's operation.