Coolant over pressurising

[Eddie96]

I've just purchased a mk7 gtd. When driving the vehicle home the coolant light flashed up saying low coolant. Stop and checked the coolant level which the bottle was empty. The next day I check the coolant level again to see how much coolant i needed to put in and to my surprise the level was up to the max line again. Ive check the heater matrix pipes to see if one was cooler than the other but I cant feel a difference. I've checked both coolant reservoir and dipstick for the oil in water and creamy stick but nothing. Its like the system is over pressurising but I cant seem to figure out why. Any help would be massively appreciated

Thanks

[joe6]

Since coolant cannot be compressed and you have not been able to find a leak the possible alternative is air in the system. That would be my first area to explore.