Cooling System Over Pressurizing

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thepiper57
Posts: 2
Joined: Tue Mar 30, 2021 4:38 pm
Currently Drives:: 2003 Megane II 1.9 diesel engine code F9Q

Cooling System Over Pressurizing

Postby thepiper57 » Thu Apr 01, 2021 7:34 am

Hi, new here so hello to everyone interested in these cars !!
I have a 2003 Megane II I bought as a project in Spain for something to do and it has some problems to say the least let me explain......
The water system is pressurizing to at least 1.9 bar so I have performed the following work:
Removed the original head had it skimmed.
Replaced skimmed head with new gasket and bolts
Replaced the thermostat and gasket
Replaced the water pump and gasket
Replaced timing belt with the kit

Still over pressurizing so I bought a good cylinder head replaced still the same problem.
Joined the two oil cooler pipes together to check cooler integrity
Cooler has no problems either blocked or oil in water or water in oil.
removed new thermostat replaced with old one but removed thermostat for full flow
Still same problem.
I have equipment to test the water system: Pressure testers and Vacuum testers both are indicating no problems.
My questions are simple, how can a water system pressurize, could the block be damaged? or can anyone explain to me what I should test next?

Your help is appreciated :-(

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