I've just been through all that!..you have my sympathy. I take it you are losing coolant rapidly? If you are sure its coolant thats coming out the exhaust, i.e. steam not smoke - then your head is probably cracked. What made you change the head gasket? Did the smoking start after you had over heated it? I ended up putting a recon head on mine (cost £170plus VAT) problem solved. But before you go down that route be sure it is coolant you're burning. Things to check. If the gasket work and skimming was done by a garage, ask them if the head was pressure tested whilst they were at it. If not ask why not, and kick up a fuss. If you did it, did you get all surfaces clean properly before you put it back together? Ultimately if the head hasn't been pressure tested - get it done cos that will tell you if there is a problem, if there is, get a new head and that should solve it.