at first i had loads of water coming through the exhaust..... like litte puddles almost. Then some pipe in the engine bay behind the head tank leaks like crazy as the car warms, only leaks when warm. Then eventually the header tank starts to leak.

possible water pump?

recently changed to a higher temp header cap if it makes a difference.

 

more than likely head gasket

 

why did you change caps?

 

the way i tested pump was to warm it up on tick over and if it boiled befor radiator got hot it was obvoius the water was not circulating from ether pump or thermostat not opening

 

I changed the cap to a fancy Buddy Club one, just for looks i guess. Well the water is being forced out within 5 mins of the car being on.

 

Just done a simple test, turned the car on without the header tank cap, no bubbles or fizz...no mayo type stuff inside or around cap? All the water does is.... rise up and start over flowing.

 

thats because it not under preasure due to removing cap so water will not heat up more than 100 deg c. under preasure it heats up more if sumat wrong.. id put original cap back on and see but but having a higher blow off cap might of done something due to more preasure than parts can take. if old cap was realesing preasure it might if been a warning sign for weak pump or faulty thermosat but not realesing preasure by higher cap might of blown sumat else now hopefully not..

if water overflowing when reved up pump might be ok so id cheak thermostat is opening

 

could i have caused a problem with removing aircon and the extra fan (passenger side)? theres four massive fuse/resistors under the bonnet to do with fan/aircon, do you reckon theres the conflict?

My uncle who is mechanic, when seeing the car first, said its got alot of pressure built with water exiting exhaust. Airlock?(all bearing in mind this car has not bean driven for almost a year due to work being done on it) so the rad cap could of damaged sumin when emmision tests were done.

However theres a leak behind the header tank which is tipping on to the manifold etc and steaming up.

 

if preasure is building up and water going down exaust then prob defo head gasket gone preasue from cylinders is getting into water jackets and boiling up too mutch. had same on a vectra few years back from wen i drove 5 miles with a blocked cat at 10 mph. it had colapsed un be known to me anyway back preasure blew gasket took a few weeks but had to keep topping water up eventualy could only go 20miles then all water would have gone but no leaks. if not run for a bit maybe thermostat has siezed or your fan has not been working to cool rad?? i had a DAF truck overheating and inlet pipe to rad expanded like a balloon red hot but at other side it was cold due to broken thermostat and blowing off rad cap changed stat and it was fine after. rad caps are safety valves and set to certain temps/preasure and if that had not worked am sure the gasket would have gone on that too....

 

if the car has been sat for a year, first thing I would do is check the thermostat, chances are it is seized up as it will in effect just have been sat in a water mix. I would also flush the cooling system itself, hose pipe in the rad and run it through, you would be surprised in the cr@p that can build up in there (recently flushed mine when I did my timing belt and was a bit shocked with the crud that came out on an 18month old radiator :eek3

Also flush through the engine (with thermostat removed) via the top engine hose.