Tell me about it. I've just returned to the UK and thought I'd missed the whole show. Found they were to be virtually passing overhead on Sunday and went into woo-hoo mode. Sadly that didn't last long...
The techs were speculating oil smoke, so piston ring/run bearing perhaps? Now also saying possibly a glycol plume, so head gasket, or just a coolant hose/union? Not sure if there are any other possibilities, so they're covering all the bases! I'm praying for the latter possibility.
Hope the local Halfords is on stand-by.