On the basis that an oil change is done every 10,000 miles, could you effectively be replacing the oil completely if it's using a fair amount, just by topping up? As in, there wouldn't be any of the same oil left that was put in at a service come the next one?

April 2013. my CAVE was one of the first 2010.

I use this good value and meets higher than ness VAG spec. VW 502, 505 http://www.ebay.co.uk/itm/Triple-QX-5w40-Fully-Synthetic-Car-Engine-Oil-1L-ACEA-A3-B3-Spec-1-Litre-/291380992275?pt=LH_DefaultDomain_3&hash=item43d7a91913

Looks very good value! Ordered some castrol edge last night, and cheapest I found that was £10 for a litre. Think I'm going to give a few other brands a go.

best value I could find for a good spec oil

Use the shell stuff much better than castrol , mobil1 ESP is also good

On the basis that an oil change is done every 10,000 miles, could you effectively be replacing the oil completely if it's using a fair amount, just by topping up? As in, there wouldn't be any of the same oil left that was put in at a service come the next one?

Surely as all the new oil gets mixed in with the old there will always be a percentage of the old stuff left after you've added the equivalent of a full sump of new but the dilution would probably be enough to make the oil clean enough. Thing is you still need to change the filter and if there are any little bits of metal in the sump and you don't let them drain out then they will just keep building up in there and that can't be good.

Surely as all the new oil gets mixed in with the old there will always be a percentage of the old stuff left after you've added the equivalent of a full sump of new but the dilution would probably be enough to make the oil clean enough. Thing is you still need to change the filter and if there are any little bits of metal in the sump and you don't let them drain out then they will just keep building up in there and that can't be good.

Of course, I wasn't suggesting not doing a proper oil and filter change! If I had anywhere other than my driveway to do an oil change, I'd want to it more than every 10,000 miles! At least would save paying a garage to do it anyway. Was just a thought

Ordered some Shell oil, and will try out some 5w-40 next.