Coolant Loss

[Guest PAUL.V.V]

I OWN A 03 PLATE C3 AND THE COOLANT LEVEL IS GOING DOWN WITH NO SIGNS OF LOSS. OIL IS FINE, AND SYSTEM IS PRESSURISING.ANY IDEAS AND WOULD A LEAK REPAIR ADDITIVE HELP?

[paul.h]

Check if the 2 air bleed screws are not leaking - think I have seen this posted as a leak point on one of the forums. Before deciding on a head gasket failure also check the water pump and heater matrix and radiator for leaks. There should be some pressure in the system as the coolant heats up and expands, the expansion tank cap holds 1.4 barg, equivalent to coolant at 126°C.