Most makers give the actual spec for the oil needed so you're not tied to
one brand - although initially only one maker might supply the correct
stuff. I run a BMW and they were quite early in having extended oil change
intervals. But calculate the type of use the vehicle has when determining
when this should be. Mine will do approx 15,000 with mainly highway use
dropping to perhaps half that if journeys are short or more arduous. Using
the specified oil. I read a one model BMW group with some 1500 members and
there's no indication that sticking to those intervals shorten the engine
life. Basically, worn out engines are unheard of - although cooling issues
and plenty others exist on the engines used in this model which can be now
15 years old. But not worn bores, bearings, camshafts etc which would
indicate insufficient oil changes.
It's an interesting concept using a cheaper oil to a lower spec but the
same weight and changing it more regularly. With three thousand mile
changes it would have to be less than a third of the price of the proper
stuff at best and that's before the hassle of getting it done. So to me
just not worth it.
I've not ever understood this US thing of changing engine oil far more
often than the maker says. Do you also change transmission and final drive
oil at the same rate? Coolant and brake fluid? Drive belts, etc? All those
can and will give trouble if neglected - same as the engine.
In a sense it's the same, because it's trouble, but it's not the same
in that those things don't have to be changed nearly as often to avoid
problems.
I'm certainly by far not the best maintainer of cars, but... I usually
buy a car when it's 7 years old and get rid of it when it's 14 y.o.
I also don't drive that much these days, but even when I drove 10 or
12 thousand miles a year, during that time, I've changed a belt only
once**; changed a timing chain only once, when it broke; never changed
the differential fluid (final drive oil?), never changed the brake
fluid except what little came out when I bled the brakes, on two
occasions***
The recommendation, except for the fancy expensive antifreeze, and
only when not mixed with regular antifreeze, is to flush and change it
every two years. I've only flushed about twice in the last 26 years,
but I do normally change it every two years. It's about 2 years now
and it looks brown and muddy inside. Probably partly because I had a
little leak and put in two kinds of stop-leak. The stop must have
worked though because I've only needed to add coolant twice in two
years. I'll flush it in the spring.
I've only changed transmission fluid twice in 38 years, and that was
only when there was a problem and I was hoping the change would make
the problem go away. People tell me it can.
BUT, engine oil gets much hotter than any of these other things, and
blow-by adds gas and combustion product contaminents to the oil, which
I think can make the oil acidic. It should be changed more
frequently. Of course I don't do that either. With my '88 Chrysler
Lebaron, with a 2.5 liter 4 cylinder engine, it had a leak but I was
depressed and never checked the oil, until, when I went quickly around
a corner, the oil light would come on. Then I would add two quarts. I
had to scrap the car 2 or 3 years later, but the engine was still good
and gas mileage was still high. But it leaked everywhere and had body
damage. In a different world it woudl have been worth fixing, but
there were so many better cars for less than the cost of fixing half
of the leaks.
Also, there is a history of changing engine oil because the
manufacture insisted on it to keep the warranty. When cars had 5 year
warranties (maybe they still do. I've never had a new car), that meant
people spend at least 4.5 years obeying the rules. Of course that
becomes a habit for many.
I had my 72 Buick Centurion with the 455 cubic inch engine for over
100,000 miles and it did well with this lousy treatment. The only
engine problems I ever had was when I had a coolant leak and after 4
months I screwed up and ran the car without enough water.
** Back when cars had ammeters, my charging seemed a little low when I
left NYC. I went all the way to Chicago, then Indianapolis, and was
back to Pittsburgh when it looked really bad, or the lights were
dimming. I pulled into a gas station just before the Turnpike and
looked under the hood, and the belt was held on by literally a thread.
A thick thread, but still less than a millimeter. When I tried to
restart, the battery was totally dead. I think I went 1200 miles
while putting less than I should back in the battery, and slowly
draining it. I had a spare belt with me and I may have put it in
myself, or maybe since it was dark, I had the gas station do it.
***(Once I was able to change the master cylinder without needing to
bleed the brakes. I left the brake lines a little lose at the master
cylinder, had someone push down on the pedal so that fluid seeped out,
and tightened the lines before he let go.)
So logic says
if you feel the maker has extended engine oil changes just to in some way
stuff you this must apply to all such things.
The reality is most modern engines if they don't break in some other way
will last the life of the car without any major overhaul like a re-bore
etc. Which means changing the oil more regularly is simply wasting
resources and money.
I hope you're right. It's been 20 months since my last oil change. I
had a fight with Jiffy Lube, which is only 3 blocks from here. (They
claimed to have checked my PCV valve but I was watching and I know
they didn't. (Not only that, the hoses were too stiff to do that
without breakign the hose.) I wouldn't have minded if they hadn't done
it, but lying to me about it is far far worse. (In fact, I woudln't
have wanted them to break the vacuum hoses just so they could check
it. When I complained he took my address and said "Maybe the company
will send you a coupon." Ugh."
