I use fully synthetic 5W40 in my 2013 R56 JCW. I change it every 12months/5000miles. When looking inside the oil filler cap at the camshafts, they look like new! No deposits or sludge build up. Not even any discolouration!
Everything looks all 'silvery' and new!
the 5 figure is the hot number at 100c the 40w is at 0 degrees so when oil is cold its thinker and when gets to 100c its 5,, trouble is these engines runs at 105c ie 5% over what oils are graded at, most engine wear happens at cold first start up so the thick oil does recuse blow past i would think might take oil pump a fraction longer to push oil around at full volume but always is higher pressure ,,, as cold oil is thicker and more dense until heats up,,
5k oil changes are by far best war forward and keeping oil level on the full mark nearly all the time,, and not do what some do drive until red oil can light comes on dash then drive to garage and put some oil it and then be all fed up that they need a new engine as when that lights comes on damage has been done,,
i done a rebuild on a r32 a while a go and after all rebuilt told the owner it will use more oil for 1000 miles i would say prob less ie little more than what vag say 1 litre to 800 miles is normal and he needs to check oil every day get a understanding on it all,,, after 1300 miles he sends me a video of the engine bay and its tapping and rattling not sounding right etc,, bare in mind on phone i asked him have you been checking oil regular he would answer the question directly,, so i got car recovered back to my mine ,, and the very first thing i do before moving any car i dont own if check for oil and water... the oil was so low was not even on the dip stick (prob on the dipstick who owned the car lol) so i videoed it sent it back to him he was so sorry etc ,,,,, i dropped the oil in to clean container and let settle and then look at the bottom of container for white metal,, lucky boy was clean i filled it back with new oil and filter,, put vag come on it all 6 cylinders were equal on fueling and zero knock and smooth running all good,... some people are just place stupid when it comes to the very basics check oil and water every 300 miles max weekly or even daily on one that uses ,more oil ie like most mini's do,,, that guy spent close to 4k on that engine with forge work etc and to lazy to check the fluids,,
what i feel was him pointing fingers at me in first place that his engine was all wrong and all my fault etc ,, i drove his car around for 3 days to make sure it was all good and never needed any oil in that time and went so well,, i even stuck it on mot emissions tester and all levels came back super low hc was 9 ie a tall tail hint of oil burning is high hc..
my point here to anyone reading it we all buy used cars that we have no understanding of whether the past owners were lazy car killers that pass on their damaged cars to next owner,,,