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      03-30-2011, 05:46 PM   #45
mrgold
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Drives: F82 M4, E82 135i, E92 M3 SOLD
Join Date: Feb 2008
Location: Los Angeles, CA

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Quote:
Originally Posted by Whoopsy View Post
This is the default BMW oil info sheet.

Notice the first section it calls for 5w-30, this oil is the default oil unless otherwise noted.

It does have a special M section, but the M section specifically only states 4 engines, S54, S62, S65, S85 that needed the 10w-60.

This means the S63 is not part of the exception.

Of note, there is a Alpina B7 section that calls for the standard 5w-30 oil, the B7 engine is derived from the N63 engine, just like the S63 engine in the X5/6M. They all uses the same N63 engine block, there are no extra oil passages on the S63 for extra oil flow, which means the heavier 10w-60 oil will no provide enough flow at the top end of the rev range.

This sheet is also the same info the BMW rep pull up when you called in. There is no special section for S63, as it is suppose to be using the dedault oil, but since it's installed in a X5/6M, with the M being the keyword he heard, he defaults back to the M section.

Btw, when talking about 'sophisticated' engine oil, BMW factory oil are API SM rated, a higher grade than even the TWS, which is SJ, or it's current form, Castrol Formula RS 10w-60, a SL grade.


In any case, if you want to continue using 10w-60, no one is stopping you. At least when your engine blow up because of insufficient oil flow, you can claim warranty on it as you DID used 'BMW Approved Oil', as told by a BMW rep. You did record that phone call as future evidence did you?
After reading this thread I am compelled to step in as wrong information is bad for our whole BMW community. The main reason I am chiming in is to correct the mistaken claim that by using the heavier weight TWS 10w-60 oil in the motor that somehow oil flow will not be sufficient for sustained high RPM situations. That simply is not true. The S63 engine is NOT going to mysteriously melt down, prematurely wear out or blow up due to insufficient oil flow at the top end of the rev range just because of using the TWS 10w-60 motor oil. PERIOD! Why?

1. Believe it or not BMW (especially M division) is not that stupid to build an engine which can be that easily damaged just because a customer is using the thicker performance motor oil (especially their own BMW approved high performance motor oil).

2. The viscosity thickness difference at regular operating temperatures 100 C (212 F) for the 10w-60 and the 5w-30 is much closer than what most people think.

Viscosity chart http://www.bobistheoilguy.com/visc.html

Viscosity of 10w-60 @ 100 C (212 F) = 21.90 – 26.09 range
Viscosity of 5w-30 @ 100 C (212 F) = 9.30 – 12.49 range

The true viscosity difference between the two motor oils at operating temperatures will be about 12 and not 30. Therefore at regular operating temperatures the 5w-30 is actually at about 10 viscosity and 10w-60 is at about 22 viscosity which is definitely “thin” enough for oil flow at high RPM.

3. Oil pressure rises as engine RPM rises. There is plenty of oil pressure @ 7000 RPM to assure sufficient oil flow for the heavier weight oil. Especially at normal operating temperature when the 10w-60 is actually only at 22 viscosity.

On a side note, I just called 3 different BMW dealers in the Los Angeles county area and 1 in San Francisco and all 4 BMW techs said the TWS 10w-60 is the correct oil (preferred) for the engine according to their service computers. One tech did state that the standard 5w-30 can be used as an alternative when TWS 10w-60 is not available but not recommended if the customer will be doing any high performance driving. That being said, there might be different recommendations for different areas with colder climates but I have not heard or seen anything about it. For me I would choose the TWS 10w-60 oil simply because it is the best oil available approved by BMW M.
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