andrew strasfogel wrote:
Gary,
Enjoy your new cars but BE SKEPTICAL OF THE M1 HYPE!
Unless 1) you live in an extreme climate (Phoenix or Winnipeg, e.g.),
2) plan on keeping both cars forever, AND 3) will do the sort of
driving that allows you to take advantage of the extended oil change
benefit afforded by Mobil 1, you'll probably do just fine with ANY
Mercedes-Benz approved ordinary motor oil.
Strasfogel fails to understand (or at least misstates) the biggest
benefits of Mobil synthetic oils (but his caution to be skeptical is
prudent). There are circumstances where a cost benefit analysis will
PROVE conventional oil to be the better value, but they involve almost
exclusively situations where a car/truck is driven almost entirely on
the highway in good weather with MANY tens or even hundreds of miles
between cold starts. Then a conventional oil with an extended change
interval is likely to offer better service when all the costs are
considered.
It is true that your engine CAN last a VERY long time using conventional
oil. It is also true that many types of engine wear are reduced (halved
or better) when using Mobil 1 oil vs conventional oil (all else being
equal).
Most modern Mercedes diesel engines DON'T wear out. Most break or are
discarded because something else breaks or wears out. Still, reduced
engine wear WILL result in faster and more reliable starting, less need
for engine maintenance and hence lower maintenance cost (you CAN even
usually go longer between valve adjustments) your battery will likely
last longer, you will use marginally less fuel and consume somewhat less
oil. Timing chains will last TWICE as long before they require changing.
In OM61x engines (like yours), timing chains often lasted less than
200kmi before requiring replacement - that interval could easily be
doubled if Mobil 1 were used for the life of the engine. In OM60x
engines, typically chain life was already almost double that of an OM61x
engine by design, which could mean a chain wouldn't need changing until
the engine turned 700-800kmi if Mobil 1 had been used from the start.
In my own cars (all change to Mobil 1 at between 100-200kmi) I estimate
the chains will probably require replacement at between 500-700kmi (at
the present rate of wear) but that will be determined finally by
MEASURING chain stretch. Cylinder wall wear MAY or may NOT be reduced by
Mobil 1 (or other synthetics) but then cylinder wall wear in Mercedes
engines is already a minor factor - it is USUAL for the original factory
honing marks to still be visible on the cylinder walls of Mercedes
engines (gas AND diesels) even after 500,000 or more miles.
It's generally agreed that cold start wear is cut by more than half when
Mobil synthetic oils are used. Timing chain wear is reduced by half.
Lifter noise in OM60x engine will be reduced (often even eliminated) if
it's already started and may not start or will start MUCH later if it
hasn't started. The engine will crank faster in ANY weather
(particularly apparent in VERY cold weather) and will start sooner and
in colder weather. This is the most obvious sign that will be obvious to
the unsophisticated user - it's DIRECTLY proportional to the reduction
in friction and that's been reported to be 25-60% (I've never experience
more than a 40% increase in starter speed - the full extent of this
increase is NOT instantaneous, but requires a little time to develop).
This will result in about a 10 degree drop in the lowest temperature at
which the car will start without using the block heater or some other
starting aid, but the REAL benefit is the reduced friction and thus
reduced wear.
If you disregard minor cost differences (labor is the major cost of most
oil changes - not the cost of the oil) or want lowest possible wear or
don't want lifter clatter on OM60x diesels - Mobil 1 WILL come out ahead
most of the time. Most other so called synthetics (those composed mostly
of group III base stock) like the ones marketed in the US by Shell,
Valvoline, Quaker State, Castrol, etc. are slightly to significantly
superior to conventional oil in different characteristics but
substantially inferior to what I call the REAL synthetic formulas that
consist entirely of blends of group IV and V oils (Mobil and Amsoil
synthetics are the most widely marketed of these in the US).
Mobil 1 synthetics can provide substantial benefits, but the engines can
still deliver FINE service when approved conventional oils are used
prudently. You pays your money and makes your choice.
Marshall
--
Marshall Booth (who doesn't respond to unsigned questions)
"der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 181Kmi,'87 190D 2.5 199Kmi, '84 190D 2.2 227Kmi, '85 190D 2.0
159Kmi, '87 190D 2.5 turbo 234kmi
Diesel Technical Advisor MBCA, member GWSection
http://www.dhc.net/~pmhack/mercedes/mbooth1.htm
