Friend just purchased 01 430CLK. The previous owner stated he put regular oil 10w30 Castrol.

Will an oil flush help him transition to syn-0w-40 Mobil-1.

Of course the dealer says ... no ... but I want to here from you ... if you have ... with positive results ... which treatment product did you use or did you go to a mechanic and hook it up to an engine flush machine.

Thanks.

 

Unless the engine has evidence of bad sludge, I don't see any need for a flush. Just go ahead and use the 0W-40 next oil change. The synthetic oil itself may have a bit of cleaning effect.

 

Engine flush is usually made from solvents, kerosene or trans fluid. Like Kestas said, skip the flush. Change the first run of synthetic out in 1-2K miles and refill.