[W126 Coupe] don't use high mileage oils

[Dick Spellman]

Chiming in on dino vs. synthetic.  While it is true that synthetic when
first used will show a higher than normal level of consumption/leakage; this
is only temporary and resolves to previous oil usage levels in about 10k
miles.  It is equally true that the only (2) viscosities of Mobil 1
recommended for Mercedes are 0-40 and 15-50.  I followed the advise of Dr.
Marshall Booth on this subject where he has clearly done the research to
back up the above information and changed all of the Mercedes I manage now
(3) 300SE's and the SEC to Mobil 1.  The first M1 change I did for each
vehicle at 5,000 miles and thereafter at 7,500 miles or 6 months whichever
comes first.

The 300's start smoothly, I discovered no leaks on (2) of them and a
continued leak on the 3rd with 300,000 miles on the speedo.  The SEC which I
have had valve covers off of for new powder coated versions had heavy
build-up of varnish on first inspection just prior to M1.  With this first
and only M1 change before winter set in, I removed just the passenger valve
cover and it looks as if the engine was just refurbished.  No varnish
whatsoever.  It seems M1 removes the gunk nicely.  I've continued with the
Mercedes recommended filters mfg. by Mann.

I would suggest Mobil 1 works as advertised and is a recommended lubricant
by Mercedes for the specific viscosities mentioned.  Just not a big deal and
very convenient if you change your own oil.  If you use a qualified shop
then stay with dino and change every 3k miles.

Dick