Thread: 5w-40 5w50
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Old 08-22-2009, 05:51 AM   #5
Brucelee
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Quote:
Originally Posted by Flavor 987S
Charles, isn't there a general rule that it is always best to have the two numbers closest together? For example a 5W40 vs. a 0W40 or a 15W50 vs. a 5W50. With the obvious understanding that the specific viscosity needs to meet the manufacturers requirements.

In general, this rule used to hold true. With synthetic oils, this is supposedly a bit less of a concern, especially for true class 4 and 5 syns.
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