I have an 02 plate Mondeo Estate, it smokes a bit when accelerating (or my dad says overrun??) and burns a lot of oil, but otherwise absolutely fine. HAve recently cleaned EGR valve as the light was coming on intermmittently but that seems to be ok. It did exactly the same last year, when the garage revved it for the emissions test it belched out thick smoke and filled the workshop, they suggested the head gasket may have gone and that the would do a pressure test on Monday morning. I drove it all weekend, initially there was a bit of smoke but it cleared within a couple of miles. On Monday I took it back, for the pressure test, but they couldn't get it to replicate the problem so they just re-tested it and it passed.
Any ideas welcomed as to what may be the cause, what if anything I can do? It has 124000 miles on the clock.