On 8/31/2011 1:44 PM, firstname.lastname@example.org wrote:
No, it's not my opinion. When the whole sludge thing happened Toyota
stated that it was the result of drivers that should have followed the
severe service oil change interval (5000 miles) following the normal oil
change interval (7500 miles). They thought it too confusing to have the
two service schedules so they rolled everything back to 5000 miles.
> If the extra oil changes eliminate the sludge/coke
> failures, they are NOT being changed far more often than "necessary"
No argument there. But it's still a far cry from the days of lower
quality oils when 3000 miles was the norm.
Like I said before - it's NOT better oils - it's less agressive
fuels and better mixture control - which allows what ammounts to a
POORER oil to do an adequate job. To be more accurate, a slightly
DIFFERENT oil - better in some ways, inferior in others.
They had a nightmare of sludged engines due to - bad PCV or head
design - not sure which if not both.
That's why they went backwards.
Nothing to do with the "severe" service schedule per se.
That's what happens when you play with intervals and the unexpected
Clare says 3000 mile changes would prevent this.
I don't follow Toyota, so i don't know.
But there are marketing reasons to take chances with longer intervals,
just as there are for the 3k change standard.
No, those who claim the driving does not meet the definition of
"severe" have their head stuck somewhere - either in the sand or
The MANUFACTURER'S DEFINITION states if ANY of the following
conditions are met -
And in a very large part of the USA and Canada, MOST cars fall into at
least TWO of those conditions most of the year.
And you guys will be the ones bitching because your Chrysler /Honda /
Toyota watever failed due to "coking" damage. It has GOT to be shitty
engineering, or bad oil - cannot POSSIBLY be because you didn't follow
the specified "extreme" oil change schedule. After all, you know SO
MUCH MORE than the engineers at the manufacturer who SPECIFICALLY
REQUIRED 3000 mile oil change intervals for your type of driving.
Remember - I was a service manager for 10 years (and a mechanic for a
lot longer than that)- and the manufacturer REQUIRED 5000Km oil change
intervals for "severe" conditions - and they spelled out VERY CLEARLY
what constituted "Severe" conditions..A few customers complained,
saying I was just trying to get them to spend more than they had to
untill I sat them down and showed them the manual - explaining that if
ANY ONE of those conditions was met, it was considered by Toyota to be
"severe" - and they met 2 or more most of the year.
Customers who followed my (and Toyota's) recommendations NEVER
suffered timing chain, oil pressure, oil consumption, or ANY other
engine problems. I can not recall ONE failure over that 10 year
period. We DID, however, do a fair number of timing chain/tensioner
replacements - a few camshaft replacements due to wear, ring jobs due
to high oil consumption and blowby (stuck rings) etc on cars that were
not regularly serviced by us - and those who stretched their
Definitely made a believer out of me.
The engineers at the manufacturer of my car tell me to rely on their
oil monitoring system. That system tells me to change at around 7000
miles. My driving includes some of the iteme on the "severe service"
Neither of my cars have the oil monitor, so I follow the schedule
(more or less). Daughter's Honda asked for oil change at under 8000km
(7200, I think) which is under 5000 miles. And that was the monitor.
Actually, it COULD. You need to know what caused the oil consumption.
Synthetic oils are less prone to oxidation, and also to boil-off. Also
less likely to coke up the rings.
Changing the oil at 3000 miles, in many cases (not Saturn specific)
can mean NO oil consumption, while leaving the engine untill 5000
miles may mean half a quart of oil used - and by 8000 miles more than
And the Saturn is definitely not the only engine with a hydraulically
operated timing chain tensioner. The 2600 MitsuShitty had about 6 feet
of timing chain and balance shaft drive chains - all of which were
hydraulically tensioned. Without proper oil change intervals the
chains and tensioners didn't last well at all.
The Toyota 18R, and more so the 20R and 22R series engines had the
same issues. So did the M series engines - long oil change intervals
meant noisy timing chains. And broken tensioners. Adequate oil
changes TOTALLY eliminated those issues on the Toyotas as well.
Oil deposits - VARNISH and SLUDGE kill engines. Slowly, and steadily,
a bit at a time.
Yes, some engines (particular models) WILL survive abysmall
maintenance and severe abuse - but even some of those particular
engines WILL succum to poor maintenance.And the occaisional example of
a "fragile" engine will also survive, in spite of abuse and neglect.
Hmm, most of Europe uses km, not mi - are you sure you're not mixing up
units? I used to do oil changes around 6000mi in England (on my modern
vehicles - I still did my vintage ones at 3000mi) - which isn't too
different from 10,000km.
That's still higher than the US, of course, but only twice as much :-)
Historically, I think the US was reluctant to change tried-and-tested
engine designs, at a time where much of the rest of the world was aiming
for better efficiency and power to weight ratios. That gap seems to have
closed these days, but perhaps there's a lot of inertia left in the
system - 3000mi changes used to be the norm in the US, so that's what's
still advised even though modern engines don't need it.
(My brother in law's a GM mechanic, incidentally, and I know he quotes
3000mi - I'll try and remember to ask him why next time I see him :-)
At risk of harping:
The engineers that designed my engine say to follow the advice of
their oil monitoring system
The oil monitoring system on my car usually tells me to change at
I'm a typical driver whose driving includes some of the items on the
so-called "severe service" list
In effect, the engineers who designed my engine are telling me that,
for my driving, 7000-7500 miles is appropriate.
The manufacturers are, in effect, saying your car will last through
warranty with 7000 to 7500 mile oil change intervals. It will most
likely last as long as the average new car owner owns the vehicle.
They are not saying anything else.
On Fri, 02 Sep 2011 10:05:11 -0500, email@example.com wrote:
My bad; it was meant as a question... speculation - not a statement of
fact :-) There does seem to be a discrepancy between the recommended
frequency of changes in the US and some other countries though, and yet
surely the formulation of the oil is the same - as are engineering
tolerances, the quality of parts etc.
I suppose the US climate is extremely diverse - often in contrast to
other countries - but I'm not sure that could account for it, as if that
were the sole reason I'd think the auto makers could regionalize their
I never said that I knew better, just that I'd ask if he knew what the
'official' reason was (because it might be he's just doing what he's
told, after all).
I change the oil on the Chevy van at 3000mi, as per factory
recommendation. The Toyota usually gets done around 4000mi.
Interestingly, the Ford is 6000mi though (I had it in my head that it was
3000) - that's a 1967 build, so it seems that in the last 40-something
years things have gone backward...
On Fri, 2 Sep 2011 23:13:04 +0000 (UTC), Jules Richardson
European oils are different than american oils. There are more specs -
some significantly higher - and BMW, Mercedes, Peugot, etc all specify
exactly what oil is required for their long change intervals. Many of
those oil specifications can not be met by the oils sold in America.
Also - as far as "going backwards" - except for the removal of lead
and the associated purge chemicals and bwetter fuel mixture control,
todays engines are more highly stressed (generally speaking) than the
engines of 1967.
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