Have got a problem on my road car (1.4i Astra yr2000) where my coolant header tank is staying pressurised, even when engine cold.
This and the fact I appear to be loosing a some coolant - intermittantly, not much but means I need to check it every 2/3 days.
Keeping finding a small amount of liquid on the drive - which I assume is coolant. The oil is not milky and I had a 'coolant gas
analysis' check down at the dealer, which came back negative.

If it isn't the head gasket any ideas what could be the problem?

Yup sounds like head gasket to me, possibly cracked head allowing coolant channels to become pressurised. I had a V6 Sierra rally car with the same problem, coolant hose exploded at MOT station scalding tester and his first mate! Needless to say it didn't pass!

Yep sounds like the head gasket.

Had the same tests done on my Peugeot when I had exactly the same problems. It also showed no signs of exhaust in the coolant.

Twas the head

Cheers

Mark