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O-Rings

rozemab

New member
Question:

When I see an O-ring in the BMW catalog and is a "M88X3", is M88 the OD or the ID of the o-ring? Obviously 3MM is the diameter of the cord, right?
 
Where are you seeing this kind of callout...for what part? Typically bolts are called out as M8x1 or some such. That said, the famous white o-ring for the oil filter is listed as "44x4" (no M) and it is nominally 4mm thick with a 44mm inner diameter. Similarly, the cylinder base o-ring is called out as "93x2.2", again no M.

So, my qualified answer to your question, is that I agree with you. YMMV.
 
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