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Old 08-03-2017, 09:22 AM   #11
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Mobil I is 100% syth. They had a lawsuit a number of years back trying to prevent oil blenders from referring to their blend products as synthetic. They lost, the courts said that "synthetic" was to broad a word and all could use it.

I used to release motor oil for Cadillac and Mobil I on the Northstar engine. I use Mobil I 5W30 in my van year round. I also would be very comfortable with Mobil I 10W30 in the southeast and 5W20 in the north. Although 5W30 would be fine in either environment though. Oil viscosity recommended by the auto companies is really driven these days by vehicle fuel economy goals. For those that are really old...remember when the owners manuals listed 4-6 oil grades that could be use? That was eliminated to reduce owner confusion and help the owners focus on 5W30 oil. If the vehicle manufactures wanted to use 5W30 in the federal fuel economy test vehicles they had to show the Feds that they were actively promoting it. So most owners manuals today reflect the oil grade that do no damage an engine and also give the best fuel economy improvements.

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Old 08-03-2017, 09:31 AM   #12
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Here's some discussion on that:

In short I probably used the terms differently than what the oil industry is, and the change in blends doesn't really impact performance, but did get prices way down.


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Old 08-03-2017, 10:17 AM   #13
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My simple answer to the original question is, and I have at times bet safety and success on this, the most important choice when it comes to lubricants is to use the specified weight of oil that the manufacturer recommends. And I mean manufacture or re-builder of engine, transmission, ect. not the brand of vehicle it's in. Everything else is second and can be adjusted for, (i.e. more frequent change intervals).

As this thread has shifted to a synthetic vs conventional discussion here is a video that is a nice introduction if someone isn't familiar with the subject.

I usually put oil discussions in the same category as politics and religion. Even though everyone makes decisions on both, probably best not to discuss in depth with people you want to keep as your friends.

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Old 08-03-2017, 11:07 PM   #14
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My 2013 states that 5W20 should be used and even put it on the oil filler cap. I use Mobil 1 in that weight and change every 3,000 miles.

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