into the engine compartment they are going to have quitre a job in cleaning it all out. They won't have to remove the engine but they will have to spray it with some sort of degreasing compound and steam clean it. Particular attention needs to paid to ensuring the belts are clean (may need to be replaced) and that they pulleys are oil free (slipping belts are not functioning properly). All rubber hoses and fittings, wires and particularly electrical connections must be thoroughly clean to prevent damage and electrical problems. This is why BMW must do a thorough job.