Hi I had a 14 plate Octavia elagance 4x4 for 5 years

always used a bit of water, water pump replaced first month of ownership but still lost a bit of water (250ml over 400 miles)

recently water system has been pressuring up and bigger water loss until it blew a pipe going  to or from the heater matrix

No water in the oil or white smoke.

This is now doing my head in. been advised the thermostat is a common cause for this also the egr cooler is a known problem.

any advice is appreciated

Thermostat will not cause pressurisation unless through overheating which you have not mentioned.

 

EGR could do, head gasket leak definitely would however the pressure would be relieved via the expansion tank cap well before any hoses with any integrity would burst.

 

I would have the cooling system pressure tested to make sure someone has not played with the relief valve to hide a water loss problem, I would also do a combustion gas "sniff test" on the coolant.

Thanks. car does not overheat. stays at a constant 90 just before the pipe blew it went up to 92 then back to 90