[W126 Coupe] don't use high mileage oils

[Chiappinelli, Joseph]

Comparing synthetics to traditional oil is like comparing tires of 30 years ago with the high tech rubber available today. There is no comparison. Alexander listed the obvious benefits. Those that say dino oil is good enough because they never had any problems as long as they changed oil regularly remind me of those people who could not see the benefits of using more expensive radial tires when they first came out because they never had any problems with good old bias ply. As far as the cost difference, in the grand scheme of things, we are driving very expensive cars that deserve the slight premium of good motor oil. Change it every 4000 miles or less just to purge the engine of corrosive acids that develop no matter which oil you use. With the type of expensive modifications and restorations I see discussed on this board, it's hard for me to believe someone would use regular oil because its cheaper.

J.Chip

-----Original Message-----
From: mbcoupes-bounces at mbcoupes.com
[mailto:mbcoupes-bounces at mbcoupes.com]On Behalf Of jralex at ix.netcom.com
Sent: Wednesday, January 26, 2005 3:59 AM
To: Mercedes Coupes Mailing Lists
Subject: Re: [W126 Coupe] don't use high mileage oils


The oil numbers refer to viscosites. 15W 50 means that the oil behaves like a 15 weight when cold and a polymer pulls in the characteristics of a 50 weight when engine gets hot. So, 0W 40 is actually a straight SAE 40wt. without winter characteristics. Actually the 15W50 is better for winter but of all the superior qualities of a sysnthetic which is polyalphaolefin with a kiss of polyolester and diester. The later two are used to get the addditive package into the matrix and are nonlinear. PAO is linear and therefore able to mix with any mineral based oils left in the system. The quality of a syn. to not get thick over night which make petro based flow slowly on initial start up on a cold morning is enough reason to use it. Most wear occurs as a condition known as 'boundary condition' i.e., tne oil is not present as opposed to full film or 'elastohydrodynamic lubrication'. For the same reason you guys kill the coil after oil change synthetics get to the moving parts faster. Satish put a syn. and a dino quart in his freezer overnight and pored each into a paper cup. After observing the flow rate differance He said it was no contest. That without question He would  use Syn. especially winter in Detroit. Syn. is 30 times less volitile that dino meaning the syn does not evaporate leaving sludge components. It is far more resistant  to oxydation and chemical attack. Need I say more! Major oil companies are always looking for another category other than 'Me Too' so as to capture market share for profit. All majors have synthetics but fought it for years. Castrol started using a Group IV highly refined petroleum base stock calling it synthetic argueing that the process qualified it as synthetic. Mobile took them to court and the decision favored Castrol! The industry is in an uproar over this court crap. It is deceitful in that all know that synthetics have always meant PAO!! Enough! Richard, by the way if you go to Mobile 1, a good choice, and extend your drain intervals to 3 or 4 times as long at least DO change your oil fiter every 3K and add a little for filter loss. I have run out of typing ink. Later, Jim Alexander
-----Original Message-----
From: "Shayegan, Richard" <rishayegan at davidson.edu>
Sent: Jan 25, 2005 3:16 PM
To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>
Subject: [W126 Coupe] don't use high mileage oil
I e-mailed Pat Goss just to see what his thoughts were on going to a
thicker oil as a car ages. He said that he doesn't think it's a great
idea, and in fact he likes Benz's new recommendation for older cars too
(namely, 0w-40 synthetic). I asked him if he knew of a regular oil that
was 0-40 since I have a leaky rear main seal and don't fancy the idea of
synthetic all over my driveway. I mentioned that the rear main seal had
pretty much fixed itself after 2 years of high mileage oils though. Then
he told me that now that I've used high mileage oils, I have no choice,
I have to keep using them. He said unless an engine is in serious need
of seal swelling, don't do it, because it overswells the seals and then
the car becomes dependant on that extra swelling. He said I might be
able to still use regular oil since I'd only used the high mileage for
15,000 miles, but that even though it's only been 15,000 miles I may
still experience oil consumption if I go back to regular oil. I don't
know about y'all, but I hate the idea of being dependant on an oil,
especially one that only comes in 2 acceptable weights, so I thought I'd
give y'all a heads up.
Richard

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