There are two obvious problems: 1) Toyota specifies two intervals
upon the operating regime however it's rarely clear which regime you should
categorize yourself into. 2) at least *some* Toyota owners say they
oil regularly (no proof because who saves all their receipts) and had
I suspect (but of course have no scientific proof - aren't sealed legal
agreements wonderful?) that Toyota wouldn't have agreed to an 8-year
warranty for specific engines, unless at least *some* such evidence existed.
I happen to have one of the allegedly sludge-prone Toyota engines, and
I've looked into the problem quite a bit. The conclusion that I came to
is that Toyota wanted the engine to run hotter for reasons of
thermodynamic efficiency, so they narrowed the oil passages. They
widened them again on the next generation of engine in the 2002 model. I
have never seen a credible report of sludging on an engine that had
reasonably frequent oil changes. For a couple of years now, I have been
running Mobil 1 out to 7500 miles and getting used oil analyses, and
there is no sign of sludging.
As you say, BMWs and Mercs have much higher volume sumps, and hence have
the ability to suspend lots more "dirt" than my Toyota. BMW and Merc
also specify oils with massive amounts of additives, which gives them
the ability to neutralize lots more acid than the cheap stuff.
If I had a BMW (still only dreaming of one!) I would install a fumoto
valve (fumotovalve.com) and take an oil sample at 5000 miles, 10000 and
15000 and run analyses on all three, comparing the Total Base Number
(which gives you an idea of how much acid neutralizing ability is left)
and particulate count (which gives you an idea of how well your filter
is performing). These analyses are not very expensive; $40 gets you the
lab work plus an expert opinion.
Note that there are quite a few people on the bobistheoilguy.com forums
that will change their filters halfway through a cycle without changing
the oil because they believe the filter is the weakest link.
If you want to quote examples as a rule, my 20 year old hobby car has more
miles than that and has had maker's recommended changes only from new -
every 10,000 miles or once a year, which ever comes sooner. And the engine
is fine. On dino oil for most of its life.
3000 mile oil changes date back to single weight oils and bypass oil
filtration systems. Things have moved on a tad since the early '50s. ;-)
*Errors have been made. Others will be blamed.
Dave Plowman firstname.lastname@example.org London SW
This garage in downtown Manhattan advertises oil and filter change for
$70.00. This guy takes his car there 8:30 am sharp for the special and
picks it up later in the afternoon. He does it day after day after day.
A few days later the garage owner tells him, "Sir, I note that you have
had the oil and filter changed in your car for 12 days in a row, you
don't really need it this often".
"Yeah, but it so much cheaper than parking in downtown for the day"
replies the guy:-)
Thought it was time for some levity:-)
Reminiscent of the story of the rich businessman going to see his bank
manager on the edge of town and asking for a loan of 2000 dollars for a
The banker is puzzled but readily agrees.
At the end of the fortnight the bank manager can't resist asking why, since
the businessman did not seem to need the money.
Businessman: "I was allowed to leave my car in your car park."
"How much interest are you charging me?"
"About 8 dollars at 10%"
"Exactly. A lot cheaper than parking at the airport down the road while I
was away on holiday."
For direct contact replace nospam with schmetterling
"Vijay" < email@example.com> wrote in message
I find it interesting that you PAY EXTRA for an engineering team to figure
out stuff like the optimal interval between oil changes, then ignore their
advice. The factory honors warranty claims made where the intervals are
observed, therefore logic says the intervals are proper -- indeed, I'd
maintain that the intervals are short if the factory says they will support
the warranty if they are observed.
You should understand a couple of things, among them the fact that oil
technology has come a long way baby. If you read the owner's manual, you
would find that the intervals are calculated based on the kind of driving
the car is put to. If you are into lots of short trips, the interval is
shorter, if you drive long distances on the freeway, the intervals are
I see no need to attempt to second guess people that get paid 6-figure
incomes to figure out the optimal usage that the oil can be put to.
Your rmileage may vary ...
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