No offense, but you need to learn to read for comprehension. Nowhere do
they make a claim on that page that their 5W20 synthetic base stock
product provides better fuel economy that a comparable 5W20 petroleum
base stock product.
Why don't you show a _single_ independent study that shows a benefit to
most people. Oh, wait, they're aren't any!
After all these years you'd think that there would be at least one
published study that showed a provable benefit in terms of wear, MPG, or
extended change intervals for synthetics uses in non-high performance
engines, operated in moderate climates. But there aren't _any_. There's
anecdotes by users of synthetics, there's claims by companies like
Amsoil which have never been validated, and of course various claims by
MLM people selling Amsoil. Just choose your benefit from one of the
hundreds of MLM web sites!
Of course there probably have been plenty of studies that were done but
not published because they didn't have the results that the company
paying for the study wanted.
It's amusing that not even Mobil, who would have the most to gain by
some evidence of increased fuel economy for synthetics, can make that
claim. All we see is a heavily qualified statement that logically makes
"Actual savings are dependent upon vehicle/engine type, outside
temperature, driving conditions, adjusting tire pressure, and your
current engine oil viscosity."
Huh? So adjusting tire pressure affects how well synthetic oil works (as
opposed to how well dino oil performs, LOL). And how does your current
oil viscosity, if it's the same as the viscosity of the synthetic, make
So here's what Mobil thinks you should do:
1. Change to a lower viscosity of synthetic base stock oil than the
petroleum base stock oil that you're currently using
2. Drive only in extremely cold temperatures where sythetic has a
benefit at start-up.
3. Adjust your tire pressure, from the previously under-inflated
pressure you had with your petroleum base stock oil, to the proper pressure.
Geez, some people are gullible.
Far as I'm concerned, SMS is a long-haired maggot-infested dope-smoking FM
type. If he was called to give professional testimony, as a judge, I'd have
the whole thing stricken from the record as being unreliable.
Of course it does, but Mobil is being disingenuous when they claim that
tire pressure has an effect on how well their synthetic base stock oil
performs versus how well a petroleum base stock oil performs. It makes
no difference. You should keep your tires properly inflated no matter
which type of oil you use.
And if you change from 10W30 petroleum base stock to 5W20 petroleum base
stock you'll see the same change in fuel economy. Of course you should
not make that change no matter which base stock you're using, but that's
another matter entirely.
Mobil is trying to get people to change multiple variables at the same
time, one of them being the base stock of the oil, then claiming the
increased fuel economy from switching to a lower viscosity oil and
proper tire pressure is due to the change in the base stock.
Even for their "Advanced Fuel Economy" formulation, the increase in MPG
isn't due to the base stock being synthetic, except for the fact that
apparently it's not practical to make a petroleum base stock 0Wxx oil.
Even then, they're hedging their bets, admitting that the advantage is
during start-up, not during normal operation.
I used to work for a company that made polymer or synthetic additives to
prolong oil life, I am also old enough to remember when it was normal to
change oil ever 3000 miles, but due to additives now the oil wear is
less, modern oils allow for annual changes or up to 20,000 miles between
changes, that's what synthetics are all about.
( Yes it wears out due to the shear forces in an engine chopping up the
long chain molecules into shorter runnier ones, lowering it's viscosity
and therefore protection.)
Yes, longer change intervals is what synthetic is good for. When Mobil 1
first came out, Mobil was promoting 25K miles between oil changes, but
they quickly backed down from that recommendation because they didn't
want to be liable for warranty issues resulting from owners violating
the required oil change interval in the manual.
Now the longer change intervals are finally making it to the U.S.. The
Mini Cooper is at 15K miles now with synthetic. Going beyond 15-20K is
dicey, not because the oil no longer lubricates, but because of the
acidity caused by the by-products of combustion. If you could add some
more additives that neutralize the acid, you could go even longer.
actually, it's stability of the base oil, not so much the additives.
because the base is highly refined, it doesn't have nasties in it like
aromatics, branched chains, sulfur, etc. thus the base, 1-decene for
example, is highly stable, and so doesn't break down. indeed, 25k was
mobil's original stance on synthetics because it was a real number, and
they were prepared to unconditionally guarantee it too. but it's not
good for sales and dealer service profits, so they backed down. you can
try it yourself though - just send oil in for analysis and see how it's
actually, "synthetic" is hokus pokus. been to the auto parts store
lately? looked at brake fluid? noticed how there's a premium on
"synthetic"? well, /all/ brake fluid is "synthetic"!
for motor oil, provided the base stock has the required formula, it
doesn't matter whether it was refined or synthesized.
one more thing - despite the fact that "synthetic" motor oils can indeed
be superior stuff, their price premium is a rip compared to production
price. in indonesia where there's a large g.t.l. [gas to liquid]
facility that manufactures a lot of the world's synthetic oil base
stocks, the stuff they don't sell for lubes is sold as diesel oil. yes,
it's that cheap.
Where do you live? Have any experience driving in sub-arctic zone where
they never shut off engines once it is started in winter time? Even
where I live, it is PRETTY cold in the winter. Including wind chill,
temp. can reach down to -45F or so. Synthetic oil DOES make big difference.
Actually one benefit of the synthetics is that the superior base stock
needs less additives to maintain viscosity, so you get more base stock
and less viscosity modifiers.
Synthetics become acidic, and eventually become saturated with suspended
soot particles, just like regular oil.
An oil analysis is a good investment to determine the optimum oil change
interval, but since you really shouldn't be exceeding the manufacturer's
requirements during the warranty period, and the manufacturers are very
conservative, there's no benefit to using a synthetic if you're doing
7500 or 5000 mile oil changes (except in very cold climates).
/all/ motor oils become acidic. that's because of combustion product.
er, the whole point of using analysis is so that you /know/ the
condition of the oil. wtf would you disregard analysis in favor of
> during the warranty period, and the manufacturers are very
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.