Changed head gasket in summer, cylinder head bolts to 20nm plus two 90 degree angles.  Recently the radiator fan switch failed whilst driving, lost coolant which got blown out the thermostat housing body.  Replaced the fan switch and put a new thermostat housing including the thermostat and the temp sensor.  Having driven the car am loosing coolant and the top and bottom pipes to the radiator are under a lot of pressure even after a couple of hours of the leaving the car to cool down.  When I open the expansion tank cap a load of coolant is blown out the cap under pressure and down the side of the tank when engine is cooled down.  The radiator fan is working, also when car is up to temperature I am seeing coolant flowing back into the expansion vessel through narrow pipe, so am thinking the water pump is also O.K, also temp guage on dash is reading at the half way point.  Scratching my head now trying to think why am I loosing coolant and why is it so pressurized.

 

Any Help would be appreciated.

 

Victor

Because your head gasket has gone again and you're in denial about it. Sorry.

i would have the coolant tested .... its possible that it has gone again ....

also if the system is drawing air in somewhere it can have similar symptoms .... the new (bmw) mini has a similar prob where the crappy plastic thermostat housing draws in air to the system over pressurising it 

Blocked radiator?

Forgot to mention car is 1.4 MPI.  Do you think it would be worth trying to torgue to cylinder head bolts up a little bit to see if that makes a difference  and if so by how much would you recommend.  Just hoping not the head gasket again.

 

Thanks

Victor

Forgot to mention car is 1.4 MPI.  Do you think it would be worth trying to torgue to cylinder head bolts up a little bit to see if that makes a difference  and if so by how much would you recommend.  Just hoping not the head gasket again.

 

Thanks

Victor

 

No, if the gasket has blown that means it's damaged and no amount of bolt-tightening will make any difference.

Only thing I was thinking was that I tightened down the cylinder head in the summer when installing new gasket to values given in the haynes manual and I was wondering if they were correct.  Will change gasket if needed, just trying to make sure I have got to the heart of the problem.

 

Thanks

Victor