> From: John Wroclawski <jtw@lcs.mit.edu>
>
> From: Robert Jones <bobj@meaddata.com>
>
> BTW, I'm running Castrol 20W-50. I suppose I could switch to a lighter
> oil but this seems like it would only treat the symptom.
>
> This seems a little heavy for an engine in good condition. Any reason
> not to go to 10W-40?
Yes, but only if you plan on leaving it in your engine for more than about
3000 mi. (or 6 months, whichever comes first! :^)
This has been debated quite a bit here in the past, but the summary is:
the large amount of viscosity enhancers that need to be added to the 10W
base stock to get a 10W-40 oil make it unstable over temperature and time.
10W-30 (or 20W-50) don't have near the amount of enhancers, so don't have
the stability problem that 10W-40 has. (In most new cars you will void
your engine warranty if you use 10W-40!)
Pat Vilbrandt John Fluke Mfg. Co., Inc. Everett, Washington USA
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"Read dozens of books about Heros and Crooks, and I learned much
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- J. Buffet, Son of a Son of a Sailor
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