OK the final scoop on SAE 5W-20 and SAE 0W-20 oils

[Conticar]

Quote from : synlube.com

You will definitely get better mileage with SAE 5W-20 then SAE 5W-30 oil, but not by much, usually the optimistic estimates are LESS than 1%. The bad news is about 30% reduction in engine life (from 100,000 miles or 10 years to 70,000 miles or 7 years).

 

Only manufacturers who have 3 years or 36,000 miles powertrain warranties currently recommend SAE 5W-20 oil to be used in their NEW 2000 through 2006 model vehicles (FORD, HONDA).

 

By contrast Mercedes-Benz that offered 4 years or 50,000 miles warranty not only specified SAE 5W-40 motor oil, but in the USA, to assure that only that oil grade was used, provided periodic maintenance FREE to all its customers. (Free maintenance was offered by Mercedes-Benz from 2000 model years through 2004 model year, it was cancelled on 2005 model cars and SUV's)

 

ALL heavy-duty engine manufacturers recommend SAE 40, SAE 15W-40 or SAE 5W-40 oil.

FINAL choice is yours, you can get BETTER mileage, or LONGER engine life.

[Cyberet]

ah huh.. yes.. my 2002 mazda (ford) recommends SAW 5w-20

 

MB? why pick MB as a comparison?

[Genie47]

We are driving street cars here not Caterpillar trucks or diesel bashers. 10W30 is a good compromise as I have urged all to consider. 10yrs is about fine by me. COE is 10yrs. Most of us would have called it quits with a car should we stick with it by 7 or 8yrs. What happens after is not our concern but someone in Jamaica (they receive most of their cars from us).

Edited January 16, 2006 by Genie47

[Firstcall]

what is the logic/science/mechanics behind these recommendations?