Just taken my car 03 mondeo 1.8 petrol for its pre mot and the bloke says I am not going to be able to get it through the emissions due to it giving out a lot of blue smoke at about 3500rpm when you hold the throttle for a minute or 2.he says he has seen it before but isn't sure what causes it and in the past hes advised replacing the engine instead of spending time trying to solve it,seems a shame to scrap the car as it drives great and is still good on fuel etc

anyone know what causes it? and is there a quick/cheap fix?

it has done 125000 miles,hes says he has seen it happen at 70000 on other ones though