Best oil for the A-Series

[abri]

Thanks for the useful info. That point #3 is good news especially.

[Alpenflitzer]

I am using the Millers Classic Mini Oil 20W50 which has all additives in the engine and gearbox needs. We have temperatures between +35 (on autobahn sometimes 38-40 Celsius) and  -25/30 Celsius in Winter. Living in the mountains the winter can be really hard. I use Millers all year round.  In case of need on a trip I used also Harley Davidson oil which is next o Millers and has a very good shear value.

API Rating SB 
?

• API SM (better than API SC bis SL), JASO T 903:2006 MA2     This oil is used by Harley Riders.  It is mineral based. it is also specially recommended at high temperatures.
  

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  Hi All,
  
  I have seeked the advice of a tribologist and asked all the questions that were asked in this thread.  As posted earlier in this thread I had a lot of faith in Delo 400 due to its high levels of ZDDP and good results reported by the 4x4 community with this oil. After I overhauled my Mini's gearbox I started using Delo 400 but found that it was quite noisy and the oil pressure dropped to 10PSI (0,5Bar) at idle when hot.
  
  I have always used Castrol GTX 20W50 in the past so I did a search on the specs of this oil. I came across this blog https://540ratblog.wordpress.com/ He tested over a 100 different oils and graded them according to its protection ability etc. I was surprised to see that Castrol GTX 20W50 rated higher than many synthetic oils as far as film strength and protection is concerned, despite the fact that it has a relatively low ZDDP concentration. you can read my questions and RAT's reply here https://540ratblog.wordpress.com/about/ at the bottom of the page.
  
  So to summarize:
  1) IMHO Castrol GTX 20W50 is the best oil for the A series, regardless what some skeptics and naysayers with anecdotal evidence say. Offers remarkable protection for the A series despite it's relatively low price.
  2) You need an oil with at least a 50 hot viscosity rating, It would be great if you can find and oil with a low W rating such as 5 or 10W however in our climate the 20W does not provide too much of an issue when cold.
  3) We do not need to be concerned with the friction modifiers and polymers in the oil being damaged by oil shear in the gearbox as modern oils do not suffer from this condition and subsequent sludge anymore as long as oil change intervals are not exceeded.
  4) Keep oil changes to the prescribed 5000 miles (8000 km's). Changing at 5000km's is good insurance especially if you don't drive that often.
  
  Read the blog and you will have a far greater understanding of lubrication and the test results and see that good old GTX is a clear choice for the classic Mini A-series.
  
  Regards
  Deon

  
  Our- European recommendation - oil changes are recommended every  5000 km from the factory.