Alhambra 1.9tdi high water pressure

[Dwayne]

My Seat Alhambra 1.9tdi is having problems with high water pressure. it seems to be ok when the expansion tank cap is off but as soon as i screw it on it becomes pressured and bursts a pipe. I have had the head gasket changed but still it pressures. It also doesnt show on the temp gauge that the engine is getting hot but the water is overheating and I do not seem to be getting any hot air through the heating system inside the car. I wonder if its the pressure release valve but haven't a clue where this is. I have replaced the thermostat and when one of the pipes first burst I noticed that the plastic junction that connects the pipes up had corroded which I replaced with a copper one, could it be that a piece of corroded plastic is causing a blockage somewhere?? please help. Dwayne

[Dwayne]

Well I take it no one can help me then??

[kenney]

Have you checked the coolant pump impeller

[kuba78]

Hi, I have the same problem in my Audi a4 1.9tdi (B5).
It must be related with head gasket or head itself.
Propably there is a hole in the head between 3rd and 4th cylinder and it gives the pressure to the coolant.

[kenney]

Before you go pulling the head off,check the coolant pump impeller,you could also try to replace the expansion tank cap

[Dwayne]

But do you think that it would still be losing water if the impeller is broke? Also would it build up such pressure that it keeps bursting pipes??

[kenney]

Quote from your first post (but the water is overheating)you have replaced the head gasket and assuming you have done the job properly and there are no cracks in the head,I rest my case