Motor Oil wive's tale??

[Jeff/Illinois]

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[HoarseWhisperer]

Ah, good one Jeff.

I'll follow this one with interest, since I use Castrol GTX 10W-30 in the cooler seasons, and Rotella T 15W-40 in the heat of the summer.

I haven't been able to find 10W-31 for my 1931 model year.

[J Franklin]

Changing brands with the same rating has never hurt any engine I have run.

[ford1]

i have always bought what was on sale, valovline, havoline, quaker state and penzoil, for over 50 years, ive put 100,000 miles and several of my cars and never had an engine failure because of oil, its more important to change oil and filter than worry about brands

[newshirt]

This follow-on question should be good for a laugh: Is there any significant difference in non-synthetic oils these days?

I assumed all non-synthentic oils were the about same, and it was just the marketing and color of the container that differed.

[JohnW]

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That used to be the case when Fast Freddy was a boy. Any more however, as long as you use a quality motor oil that has the current API rating on the bottle, it does not really matter if you change brands. The trick is to change it regularly so that the oil is always clean in your engine. Some people think oil wears out. It actually does not wear out. It gets dirty and the chemicals that each oil company adds deplete over time. I work in an office where we literally buy millions of gallons of oil and grease each year from every refiner you have ever heard of, and some that you have not. They all start with basically the same petroleum base stock that is purchased from one to ten vendors. Each company like Valvoline or Castrol then blends their add packs (chemicals) into the base stocks and puts it in the bottles you see in the store.

Incidentally, did you know that synthetic oils like Mobil 1 and Castrol Syntec are not actually truly synthetic? They start with petroleum base stocks and have huge amounts of synthetic chemicals added in. If you add enough synthetic chemicals to a petroleum base stock, you are allowed to call your product a synthetic oil. That is why there are synthetic blends (less chemicals) and 100% synthetic (lots of chemicals) oils.

JW

[mot]

i have over 200,000 miles on my S-10 and drive it hard
and ,and 297,000 on my 4runner
i use any brand that i can find cheap
like chevron,shell,valvoline etc
neither vehicle uses any oil between changes,and never had an oil related problem
and i even mix them during an oil change

[PC/SR]

When I worked in a Shell station many years ago we were told to tell people not to change brands because it would ruin the additives, so stay with Shell. I think it was an old marketing ploy to build brand loyalty. Never heard of it causing a problem.

[Aok]

Any modern oil is going to be better then what they originally ran on

[mrtexas]

Originally Posted by JohnW

Incidentally, did you know that synthetic oils like Mobil 1 and Castrol Syntec are not actually truly synthetic? They start with petroleum base stocks and have huge amounts of synthetic chemicals added in. That is why there are synthetic blends (less chemicals) and 100% synthetic (lots of chemicals) oils.

JW

You are correct about Castrol Syntec. It is made from crude oil fractions. However in days past the base stock was simply separated from the crude, a crude with high quality lubes in it naturally. Castrol Syntec is made from vacuum gas oils from non lube type crude that has been hydrocracked to make the lube base stock.

Originally Posted by JohnW

All automobile lube oils synthetic or not have large amounts of additives, typically 30% of the blend or more.

If you add enough synthetic chemicals to a petroleum base stock, you are allowed to call your product a synthetic oil.
JW

IMHO this is not correct. Mobil 1 is the only one made from ethylene, a 2 carbon chemical. It is a designer chemical. Lube oils are typically an 18 to 34 carbon chemical.

There was a lawsuit a few years back that Mobil lost about what was considered synthetic. Mobil contended at the time that synthetic oil was made from ethylene and hydrocracked lube base stock was not synthetic.

Remember how Quaker State lube oil used to be advertised as from "Pennsylvania crude" and then from "Pennsylvania grade crude"? Apparently the crude oil in Pennsylvania was naturally high in good quality lube oils. When the PA stuff ran out other crudes were found that lubes could be made out of like Arab light, Isthmus light, and Mid Continent Sweet. These 3 were run at various times at the Refinery I was a chemical engineer at.

In the early 80s I used to schedule the production of lube base stocks.

[hardtimes]

Originally Posted by mot

i have over 200,000 miles on my S-10 and drive it hard
and ,and 297,000 on my 4runner
i use any brand that i can find cheap
like chevron,shell,valvoline etc
neither vehicle uses any oil between changes,and never had an oil related problem
and i even mix them during an oil change

AMEN to that ! I use what's available for my modern iron and mix/match all the time...forever
Only exception is 15 - 40 Rotella for my wussy A , as she gets special treatment

[Vanspeed]

I use shell rotella, has the added zinc in it.

[Russell in Tulsa]

Back in the fifties or sixties my dad said don't change oils because the rubber seals had different shrink/swell properties and may leak at the mains if you changed oils. I believe because he always used Havoline 30W in his '54 Ford and he had to use a different brand once and noticed dripping before he went back to the Havoline. He said the dripping stopped shortly after switching back. So he would only use Havoline from then on.

[dave in australia]

In my old hemi 6 valiant ute I had, I would just put any brown slippery oil in. I didn't care what brand or grade, it just went in, as long as it was the cheapest. The engine didn't care and kept on going, but then again, it was a hemi 6. The old wives tales are just that, old wives tales.

[Paul_nz]

I see no issue in blending of oils, what I do know is that "modern oils" are not overley good for our older engines. There are some good posts on ZDDP additives and or the lack of additives in modern oils. IMHO SG rated oils are what we should be using.