Can you "feel" a difference after a regular oil change?

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.

 

One reason why synthetics last longer is they already have more
additives. The additives often cost more than the base stock oil.

Jeff

 

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
doing.

 

Hi,
How about starting with definition of synthetic?

 

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.

 

Hi,
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.

 

Hi,
Dull people can't even imagine, LOL!

 

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).

 

Yes, it's true that synthetics have a benefit in extremely cold climates.

But go by the actual temperature, your car engine doesn't care about the
wind chill, which is solely for body heat.

 

If I do it myself - No change... If I have it done by someone - most
definitely!!!! My wallet always feels much lighter!!!!!!!!!!!!

DaveD

 

What a complete lot of nonsense. If the lubricity of the oil changes
in any perceptable degree, the engine bearings will fail. Particle
entrainment in the oil does not increase viscosity. Incidentally
where are these particles coming from? Surely you are not suggesting
these are metallic particles from engine wear. Where do you people
get their technical education from?

 

Just like after a thorough car wash.

 

Or a new set of JDM "speed" decals... ;-)

 

the oil does indeed make a difference - i'm talking about the word.
"s-y-n-t-h-e-t-i-c" is primarily a retail marketing device. "group IV"
is what the industry uses.

 

/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
guesswork?

 

you've worked with cars for /how/ long???

how odd - when you /measure/ viscosity over time, if the base doesn't
degrade, viscosity goes up! strange how misleading measurements can be!

er, it's called "combustion product". ever heard of that in a
"combustion engine"?

there's all kinds of crap in there. anything too small for the filter
remains in the oil. duh.

clearly a much better place than you.

 

If you're changing every 3-5,000 miles, then most likely you won't/
can't detect a difference. However, if the oil level was down a quart
or two, and was excessively dirty, then I can at least entertain the
possibility that it would make a difference with fresh oil hitting all
the lubricated surfaces inside the motor.

After changing the oil on a friend's car after 11K miles between
changes, I recall that it seemed to idle smoother and quieter
afterward.

 

Well, not being a mechanic, I would've guessed the engine is controlled
by a tightly timed ignition system rather than how lubricated the engine
is.

Al

 

Mine runs better just after it's washed and even better if I get it waxed too.
--
gburnore@databasix dot com
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