Got a 1.2 Corsa 2009 with a bit of an issue with the coolant. The coolant is going down slowly over a few weeks of driving. This is a mix of short and longer journeys. Looks like there is oil in the coolant and sludge in the tank. The oil itself on the cap and dipstick looks clean and no sign of coolant mixing into the oil. Car drives fine and no power loss etc. Timing chain is noisy so I was wondering whether the coolant symptoms point towards the timing chain gasket failing rather than the head gasket failing as I have no other signs of that.