I had a water pump seal go on my GTS300 (18k km/ 20214) which resulted in my oil getting contaminated by the coolant. There was no noticeable power loss, now white smoke and the leak must have been small, but the oil definitively had chocolaty/milky appearance.
I opted to replace the water pump cover for speed/costs reasons and flush the engine with the motul engine clean product before the oil change. You add the product (100ml) to your old oil, run the engine for 15min and do your oil change.
I can report a much more gutsier response to the throttle, easier start and overall a livelier Vespa after the service. Good result in my book despite my initial scepticism. Some carbon/dirt residue was visible in the old oil. amazon ratings of the product are also raving.
So yes a great product that i will continue using on my other motorbikes too.
