water pushing out of the header tank cap

on my p38 -98 diesel , water is pushed out of the header tank cap .
the cylinder head is according to the seller (a used car dealer , have no reason to doupt) renovated , no signs in the engine oil , and no particular smoke frome the exhaust.
could it be thet simple that either the thermostat is blocked , or the cap needs to be changed for a fresh one ??
H.Wingren
Malmö /Sweden

How long ago was the work done? could just need bleeding properly? hopefully?

wasn´t that long , and there´s not been a lot of milage since it was done ,how do l bleed the system properly ?

Check the pipe from the top of the rad is clear and that the expansion cap is really firmly screwed down, they go tight before they seal.

hopefully i am wrong but you poss may have leak in block/head allowing cooling system to be overly pressurized by escaping exhaust gasses.I think there is test that involves a blue liquid to confirm if you have exhaust gases in your cooling water - some say you can smell the gases by smelling the coolant???

hairline crack in the gasket possibly

There are two thin hoses going from the top of the header tank , one is connected to the radiator , but the other one has been plugged at the end , is it supposed to be connected somewhere , or is it a overpressure hose that is to evacuate water out in nowhere???

Cap? Thermostat? Water pump? Check rad for even temp both sides. Static test needs doing on header tank and cap. Heads can crack around pre-combustion chamber inserts.

wingren said:

There are two thin hoses going from the top of the header tank , one is connected to the radiator , but the other one has been plugged at the end , is it supposed to be connected somewhere , or is it a overpressure hose that is to evacuate water out in nowhere???

Click to expand...

Yes, this is the overflow pipe from expansion tank, and SHOULD NOT be plugged.

wingren said:

There are two thin hoses going from the top of the header tank , one is connected to the radiator , but the other one has been plugged at the end , is it supposed to be connected somewhere , or is it a overpressure hose that is to evacuate water out in nowhere???

Click to expand...

One should go to rad other is overflow. And should not be blocked.

thought so , and it´s not anymore , it was the one closest to the bulkhead that was plugged ,and the one closest to the front runs to the radiator , is that as it should be ?

wingren said:

thought so , and it´s not anymore , it was the one closest to the bulkhead that was plugged ,and the one closest to the front runs to the radiator , is that as it should be ?

Click to expand...

Yes.