Getting my oil changed shortly as car has done 13,000 on same oil (longlife) can i use an engine flush prior to servicing.......which one would you guys reccomend? heres what ive used in previous cars (but not in a PD ENGINE) MY CAR A4 1.9 TDI 130 2002 Diesel Engine Flush A synthetically fortified oil additive, designed to quickly clean inside of a car or van engine before an oil change. Removes harmful deposits, sludge and soot. Neutralises harmful acids. Leaves engines clean, ready for new oil to circulate freely. Helps to free sticking valves and piston rings. can be used prior to oil change works as you drive.