I need to change the oil on my '05 Cooper. I want to use something else then the recommended MINI oils. What is a good brand (Castrol or Mobil) and what viscosity should I use?

 

I'm coming from the Porsche world, so I can't speak with authority. However...I liked mobil1 alot. Seems to work well and stay pretty clean and not breakdown easily. But one of the best oils you can get is any commercial ("C" rated) oils. This is like Rotella-T or Delvac I think is one. The commercial oil is supposedly for diesel trucks etc. but it is one of the best oils as it doesn't breakdown as fast and his held to much more stringent testing than regular grade automotive oils. Also the lower weights of oils (5w30, 10w30) have more friction modifiers in them which cause them to breakdown prematurely when compared to the heavier oils. This is because the friction modifiers are not able to with stand the shear forces with out eventually degrading. Therefore more friction modifier= faster breakdown of oil. Also more friction modifiers are found in oils which their weight ratings are further apart then closer together...for example 5w50 would have way more friction modifiers in it than 20w50. However shear stress is not nearly as important in a standard engine such as the MINI has, often times it becomes a problem with motorcycles in which the engine oil also lubricates the gearbox and wet clutch. Also keep in mind your lighter weight oils will be more efficent as far as fuel is concerned because it causes less friction due to it's lower viscosity. That said, there's alot of information out there, you just have to learn about the oils and make a decision as to what's most important, engine longevity, oil quality, fuel economy etc.

I use mobil1 20w50 synthetic in my 944.

 

I am certainly not an expert on oil. But when I bought my '06, I did ask my dealer the question of what oil to use if I change my own oil (which I do, I am not driving 200 miles every time to have him change it). He recommended 5-30W Castrol fully synthetic. If you change your own oil, the biggest problem you will have is finding a tool big enough to fit the oil filter housing to remove it. The dealer said it wasn't a big deal to use another brand, but whatever it is; be sure it is fully synthetic, and be sure it is fairly light oil as it is a tight clearance engine.I am sure 20-50 would work, but I am not sure I would want to use that heavy of oil in my Mini.

 

If the dealer recomended the light weight oil go with it. Porsche recomends heavy weight oils for the 944 so that's why I use it. It gets nasty lifter noise if you use light weight oils.