OK will explain.
After great results with an American product called 'Auto-RX' in 5 different motors over 10yrs I last night added to my 07 A6 Quattro 233 and changed the oil filter.
The plan is to run it for 4k miles, change the oil and filter and run for a further 3k miles and change filter and oil for long-life flly synth.
But the question is will a semi-synth 5w30 be ok for the rinse phase? Reason asked is that:
a) Fully's a waste of money for such a short (3k) change duration
b) The product works better on mineral and semi than it does fully
As to the efectiveness of the product I did my Jag XK with it three years ago, when my local specialist (who has always maintained it) removed the inspection covers he asked me if I'd dropped a new engine in remarking "I've not seen a cleaner engine...even just off the production line"
First time I've ever used it in an oil burner though...so will let you know the results.