Quote:
Originally Posted by grumpy in NH
I am a degreed retired, Bell Laboratories Mechanical Designer/ engineer,experienced race engine builder and high-end automotive electronics package designer with a blooming interest in tribology. In my experience You CANNOT design an engine to specify 5W-20 and 5W-30 given the LARGE difference in operating viscosity at 100C. I Do NOT have issue with engines designed exclusively for 20 weight and agree to the successful application. But Toyota continues to specify a broad spectrum of oil weights and this is a recipe for disaster. You have no data as neither do I have (at hand) statistically relevant data on engine failure frequency; so you have not countered my arguement in any meaningful fashion. I have had three engine failures, running cross specified 5W20 oil, in various engines - so I surely do have a very PERSONAL though anecdotal sample. I DO hear the engine noise and engine noise means boundary lubrication and boundary lubrication means engine wear over useful life - especially given current poor API standards for EP add packs. I stick to my guns and you have presented me with no data. Quote US (with footnote) some meaningful data.
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First you make affirmative (not passive) claims that are ouright lies, then you follow up with admitting that your affirmative claims have no data to back them up. What kind of engineer are you? It seems evident by your many claims and unfounded affirmations that you are ignorant.
You can try to impress with a long list of so called titles and degrees, but the bottom line is that your many posts here, and at YarisWorld.com belie your so called titles, and run contra to the thinking of the tribologists at BobIsTheOilGuy.com.
I would rather trust the engineers at Toyota, then you, an internet personality showing no proof, no cites, nothing to back up your most peculiar and unfounded claims.
Go sell your bool sheet someplace else old timer.