G'mornin',

I was doing an oil change the other day, and I referred to my trusty "W123 Maintenance Library".....I was seeking the torque values recommended fpr the Filter canister and drain plug. However, just above that info is the "recommended viscosity classes".....I just happend to notice a little footnote...... "2) Except Turbodiesel engine 617.95".....so I looked closely for the little #2 in the chart....it's barely noticable in the 10W-40 column!!!

MB Viscosity Index.doc

I don't use Mobil 1.....but....I copied and pasted the following from the Mobil 1 web page....

Mobil 1 Turbo Diesel Truck 5W-40
A fully synthetic motor oil, Mobil 1 Turbo Diesel Truck 5W-40 is engineered to help extend engine life in modern turbo-charged diesel engines, even those operating in severe conditions such as towing and hauling.

So from reading the above data.....I must assume that MB does not recommend Mobil 1 in the 617.95 engines.....UNLESS there is a service bulletin somewhere...which I cannot find.....

Not attempting to upset anyone's apple cart.....but I am a big fan of Rotella T

SB

__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG

No, 5w40 is ok......... 10w40 for whatever reason, can't stand up to the heat of the turbo, 5w40 is all diesel rated oil and therefore designed to except it..........

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-Matt

EPA Section 609 Certified MVAC Technician
-----------------
Oil Burner Kartel Member #10

Ahh the smell of Diesel Fuel, it's like coffee in the morning!

My Car:

1982 300SD Turbo Diesel (231,500 miles!) RIP

1984 300SD Turbo Diesel Custom (235,500 mi on driveline.) - On Road!!

www.icsrepair.com

Part of the problem is that when the W123 was made there wasn't synthetic oil widely available, if at all. I think if you use a CI-4 rated oil like the 5W40 M1 you will be fine. I would recommend doing an oil analysis on it, and if it were me I would do an initial oil/filter change after 500-1000 miles but after that I would just have it checked at 3000 miles to see how it is holding up and then establish a good change interval based upon your engine's particular wear and contamination characteristics.

My friend had an '82 240D and we switched it over last fall to 5W40 without a hitch. I know it isn't a turbo but it is from the same era.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I am on mile 4,100 on the 5w40 synthetic Mobil 1 turbodiesel oil.....and its running smoother than ever! I'm going to change it within 500 miles since its the initial change from dino and probably cleaned out a lot of sludge...I will then run my next batch of oil for probably around 5-6k. We use the 0w40 in the '83....also going to be changed around 4,500 soon....but then run to 5k each time after that....which means only 4 more oil changes for that car (including the one coming up!) till it hits 300k! The engine has essentially no blowby....its incredible!

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)