I believe Mobil One is base 4, whereas most of the other synthetic brands are base 3 . . . ?
I may be mistaken, but I believe some base 3 brands that are sold and marketed as full synthetic here are legally prohibited from being marketing the same product as fully synthetic in other countries
I’m not a chemist, engineer, or mechanic, but as a business person, I find it interesting that someone would pay $50,000 for a car and worry about $2 extra for a quart of oil. Changing oil maybe twice a year. $50 meal but give me the cheapest wine you’ve got as long as it says wine. I use Mobil 1 in my lawn mower and snow blower. Everyone can still do as they please. Not gonna argue with any of you.
I’ve always done what one auto repair pro recommends, to choose a good oil brand & product that meets all the specs, and stay w/that same oil for the life of the car.
Everybody raise your hand that knows their api spec without looking in the manual.
Hand up! SG or better for my Corolla.
Some Mobil 1 products are base 4 stocks as is Amsoil, Redline, Ravenol and others … The expensive versions of Mobil 1 are made from Class 4 (Euro 0W40 for example) and the Extended Performance versions have more Class 4 stock but not 100%, everything else is Class 3 because of a legal case between Castrol and Mobil 1 when Mobil ONLY used Class 4 and Castrol was using Class 3 stocks and calling it synthetic.
Don’t know the API spec, but I do know I need VW/Audi’s 502 00 and 507 00 Spec oil in the Audi.
Every brand and blend of oil has its own secret blend of additives… Anti-Wear Additives to reduce friction and protect against wear and tear in your engine. Detergent additives to clean your engine by removing impurities and build-up. Dispersant additives to prevent the formation of sludge and varnish deposits. Viscosity improver additives to help maintain the thickness and flow of oil. And Friction modifier additives reduce friction between metal parts in your engine.
Oil additives are essential to maintaining the health and longevity of your car’s engine. If the various brands did not contain these additives, you would be back to changing your oil every couple of thousand miles and your engine would not have the ability to put out the horse power it does with such a smaller displacement than in years past.
Although it is important, but to a lesser extent, not all the additives “play nice” with each other…
The reason is that every brand of engine oil is formulated differently, especially with regard to the additives used by its manufacturer. Nobody, possibly except for the top scientists and engineers working in these oil firms, knows the chemistry of their engine oils. Therefore, we as consumers cannot be sure that one oil does not affect another one. We don’t know their chemistry.
So, I would recommend that you do not mix and match various brands and blends at one time… I am not saying that you cannot change the brand or blend of oil at the time of an oil change, as long as the oil meets the requirements of the vehicle manufacturer…
I have also always wondered about that.
I would remind everyone that natural rubber was a “Crucial Strategic Resource” during World War II (1941 and on…). Even today, the European Union still classifies Natural Rubber as a Strategic Resource since the EU neither produces nor processes natural rubber. This means that the block is entirely dependent on imports, mainly from Southeast Asia. Therefore, they support industry efforts to diversify supply from non-traditional sources…
The Toyota dealer had my trans fluid in the display case area. Well, near it, not in it.
Okay
Thanks for the explanation 
Pretty sure that’s not a problem now. Any evidence it is?
No, I do not have any evidence, but I’ve read this often enough to not do it… However, I use benzene and acetone in my knifmaking to clean the various aspects, clean the steel, clean up epoxy, etc… I also know that both of these are components in the blending of gasoline. I have learned through hard wort experience, that some plastic, rosins, and polymers are compatible with one but not the other…
Most experts agree that mixing two brands of engine oil can be risky to your engine’s performance. That’s because different manufacturers will use various methods of production and special additives, which means there will be certain oils that include different physical properties.
I know these experts are not “exactly Experts” but I also know the major Oil Brands will never come right out and say, “Don’t’ Blend…” Doing so because you are on the road and need a quart is not going to cause immediate damage and those who blend oils to optimize their perceived “perfect formula” are experimenting and probably running the engine in a non-typical manner like drag-racing and do not expect to exceed 100,000 miles.
And really, without a real test to compare this supposition, side by side, with different blends and straight unblended oils, there is not scientific basis…
But there are some things we have been told to never do and some folk will never do it while others will do willy-nilly… L o L . .
Don’t go swimming right after eating, don’t swallow bubble gum, don’t sit so close to the TV, you’;; go blind, don’t go outside with wet hair on a cold day, you’ll catch a cold, don’t crack your knuckles because it causes arthritis, a dog’s mouth is cleaner than a human’s…
Any case, in light of no scientific evidence, I’ll err on the side of not playing Mix 'n Match…
I haven’t found any. Plenty of ‘I think it’s a bad idea’ from non experts, or ‘I know a guy who says he’s an expert…’. Nothing from actual experts or industry sources.
I’ve been blending different brands of oil for decades, and never had a problem.
You have to remember too. The DOD purchases oil from many manufacturers. And they better blend. Or you’re not going to sell your product to the government.
Tester
Of course, we’re talking about mixing oils that meet all specs.
Don’t know and don’t need to. As long as I’m using a name brand oil in the correct viscosity for the Fords and the correct viscosity Dexos oil for the GMs, I’m in good shape. Of course I’m talking about a normal car, not a 30 year old econobox or a EuroLux that requires a boutique oil.
I also agree that I’m not driving to another store to save a couple of bucks on some motor oil.
Ok, when I write about blending oils, I am talking about a quart of this, a quart of that, like a “witches brew.”
Formula below from “William Shakespeare – Macbeth…”
“Eye of newt, and toe of frog, Wool of bat, and tongue of dog, Adder’s fork, and blind-worm’s sting, Lizard’s leg, and owlet’s wing… For a charm of powerful trouble, like a hell-broth boil and bubble. Double, double toil and trouble; Fire burn, and caldron bubble.” 
If you change the brand after every oil change should not cause any problems, I just do not believe that routine adding or including strange concoctions of blends at one time is a good thing…
As I mentioned, this crap is only good to emergencies or MAYBE chainsaw bar oil but it might not even be worthy of that.
