I use the owner's manual to show people who want to use 0w/30 or 5w/40 synth oils and it clearly shows mineral oil of 20w/50 that goes down to -10c and over 40c. My thinking is that I am happy to sacrifice some fuel economy in contrast to having a thick enough oil to increase physical protection. Especially when the car gets hot from fast driving, high traffic, or the track. To add to that we of course recommend oils with high ZDDP content. Now I know this is a simplified approach in view of what has been written here and elsewhere, but we have seen more wear and engine expiration from people using eg M1 5w/40 from a certain era vs cars with very little or even no wear that have always had a steady diet of eg V1.
I have one person who comes back to me and suggests that I've got it wrong. The owner's manual is merely a temp guide as it states elsewhere:
"Use only hydrocrack oils of quality grade API SG (US) or CCMC G4 or G5 (EU)"
Are we talking about the same thing or am I missing something?
Also it is our opinion based on information from oil co. reps that there is no pure 100% fully synthetic oil used in normal vehicles. That they all come from some base stock of mineral oil. Is this an example of marketing again? Is there really a fully 'made in the test tube' synth product out there such as this would have you believe?
http://tiny.cc/CyLG3
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