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Old 09-04-2015, 02:20 PM
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Quote:
Originally Posted by bcredliner View Post
FYI- Bear in mind, that over a 20,000 mile oil change interval there will be oil added that will improve the effectiveness of the oil and we don't know the conditions surrounding the oil change interval.
I don't think many are running 20,000 miles. I typically run 20,000 km. But in that 20,000 km, I don't add any oil. I could just about get a litre in it by the end, but I change it instead.

Quote:
Originally Posted by bcredliner View Post
We certainly should agree that oil degrades as miles accumulate on the engine. Think of it this way. How many ounces of typical oil contaminates would you pour into your engine, regardless of the oil filter you use, and put another 10,000 miles on that oil?
I think we had this discussion previously

The additives in the oil degrade, in terms of stabilizers, TBN, etc. Agree. That matters once they are used up, or reach a critical level. Until then, not so much.

However, the oil does a better job of lubricating once broken in, with lubricity improving up to something like 12,000 miles IIRC, in the study I posted previously.

Another way of phrasing the ability of the oil to hold those contaminants in suspension, is to consider the impact of sump capacity. Many with 3000 mile OCI habits are used to 4-5 quart sumps. Double the sump size, double the capacity for managing those contaminants, before requiring a drain and fill.

Jeff
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