Corsa losing coolant - head gasket?

[catso]

Recently bought a 2005 Corsa 1.2 for my Son, chose this one because it appeared to be in good condition and everything works etc and fairly low (58k) mileage.

A couple of weeks ago I noticed that the coolant header tank wasn't up to the 'cold' mark so I topped it up, checked again today and it needed 1/2 litre to fill it, hasn't done many miles since as Son's away at Uni. I can't see any leaks, all the hoses look good, no wet patches inside from heater etc. so I'm suspecting the worst case scenario of the head gasket, possibly confirmed by a 'creamy' looking gunge in under the oil filler cap.

Engine runs smoothly, no visible steam/smoke so would appreciate any pointers on how to definitively diagnose or if there's another likely cause? (water pump etc.) and also roughly how much am I looking at for the repair, presume parts are cheap but lots of labour? How difficult as a DIY - I do have reasonable mechanical abilities (rebuild motorbike engines etc.) but little experience with this type of engine.

Thanks in anticipation.

[catso]

That sounds preferable to head gasket, any idea how I would diagnose?

[catso]

SmithyAG said:

He wasn't willing to put throw any money at it so chucked a bottle of K Seal in it and it stopped the coolant loss for the next year he had the car.

Bit late returning to the thread but did this and it's been fine since, no water loss and no more mayo under the oil cap.

Think it is the water pump/gasket but £7 for a bottle of K-seal was a much simpler solution.