Issues with my cooling system

[Nathan Davies]

Hi all. I have a mk2 seat leon fr550 edition. I have issues with header tank pressurising and forcing coolant out of over flow. Iv no spared any expense on car. Recently had new belt n pump. Air inlet manifold. Thermostat. Header tank and lid replaced. The list goes on. Can anybody tell me why i keep getting so much pressure in coolant. Iv no mayo in oil, no oil in water, no obvious head issues but cant seem to stop this pressure build up

 

[mty12345]

Hi all. I have a mk2 seat leon fr550 edition. I have issues with header tank pressurising and forcing coolant out of over flow. Iv no spared any expense on car. Recently had new belt n pump. Air inlet manifold. Thermostat. Header tank and lid replaced. The list goes on. Can anybody tell me why i keep getting so much pressure in coolant. Iv no mayo in oil, no oil in water, no obvious head issues but cant seem to stop this pressure build up

Sounds like the head gasket mate. It can fail combustion chamber to water Jacket, and the oil and water are still kept apart so no mayo. You can get cheap headgasket 'sniffers', a chemical test that visually shows the presence of exhaust gas in the coolant

Amazon.co.uk

 

[Nathan Davies]

Sounds like the head gasket mate. It can fail combustion chamber to water Jacket, and the oil and water are still kept apart so no mayo. You can get cheap headgasket 'sniffers', a chemical test that visually shows the presence of exhaust gas in the coolant

Amazon.co.uk

Thanks for comment. Iv had that checked and it showed nothing mate. Im not getting any over heating either as im reffiling when light starts beeping at me. It only pressurises at high boost and high speed also. It doesn happen if i drive around at low speed normally

 

[mty12345]

No worries. Definitely sounds like classic headgasket symptoms. The fact it only happens at high boost/speed would make me think even more so that combustion gasses are getting in when cylinder pressure is high. Possible that the test was wrong as not sure what else could cause it tbh.