Synthetic Fluids W140

[Benzbug]

Hello everybody. First, let me say how happy I am to be a new member of this group! I am on my third S-class (W140 body) and just love the quality and engineering built into these vehicles!

As for my question...I just picked up a 94 S320W with 79K on the clock and in fantastic condition. I will probably hold on to this one for quite some time. It has been maintained by the previous owner with conventional fluids per the MB maintenance schedule. I do all of my own maintenance and would like to change over to Mobil 1 fluids. For the engine oil I am thinking 0W-40 and for the transmission Mobil 1 ATF. Will these fliuds be compatible with the mileage and age of my car? Thanks for you help. :-)

[A. Rosich]

As I understand, there should be no problem switching to synthetic oil on you car.

The only problem I did encounter once with my S 500 L and also posted many times on this site by other members is that if you use a synthetic oil that is too thin, you will have leaking and noise problems on your engine.

I personally use Mobil 1 20W-50, although I am at the tropics and do not need any cold weather protection. Once the dealer used 5W-30 by mistake and all type of noises began to show up the engine. Switched back to 20W-50 and everything went back to normal.

[lee polowczuk]

I just put almost 7 qts Mobil 1 transmission fluid in my son's 300e with 153k miles...the transmission was rebuilt about 10k miles. ago.... I think it's a good choice because it will be in there for 30k miles.. it was 5 dollars a quart.

I always use 20w-50 regular oil in the engines..I change it religiously at 3k miles.... so Mobil 1 would be costly for our three vehicles....

it seems someone is always having a good deal on regular oil....not so with synthetics

[A. Rosich]

As I understand, the 722.6 transmissions used on W140s can only use the transmission oil supplied by Mercedes-Benz.

As this devices were originally designed maintenance free, hence the oil should not be changed ever, the oil used is of a peculiar composition and grade.

Later on, after some fatal transmission failures, M-B started to recommend to change the oil on 722.6 transmissions, but using ONLY their original specified oil (which, by the way, is stupidly expensive $$$).

[lee polowczuk]

I dunno... Mobil 1 seems to be a universally accepted elixir

[Kestas]

Originally Posted by Benzbug

... For the engine oil I am thinking 0W-40 and for the transmission Mobil 1 ATF. Will these fliuds be compatible with the mileage and age of my car?

I once posted a question on BOBISTHEOILGUY web site and asked about the transmission fluid. Nobody could suggest any ATF to substitute the terribly expensive MB synthetic fluid. So I recommend staying with the MB fluid.

As for Mobil 1 0W-40 synthetic, the oil will do its job of lubricating very well, but people have reported losing oil because of volatility. If you live in a hot climate or do a lot of long distance driving (few startups), consider moving to thicker oils such as 5W-, 10W-, or 15W-40.

[archibald2]

Have been using 0W-40 Mobil1 in my '95 E320 since purchase last summer. No regrets or misgivings. Personally, I like to see the development of oil pressure immediately after start up;this is when lubrication is critical to the top end components in my opinion. Not wanting for this thread to spiral down into another infamous "oil thread", I will cease with further opinion.

Perhaps my oil choices are seen by many as gambles; time will tell. I have been using 5W-40 DELVAC1 in my 1982 300D Turbo for over 40,000 of its 152,000 miles and it still runs satisfactorily using ~1 quart during my 5,000 mile changes. Have only changed the oil (0W-40 Mobil1) in my '95 E320 twice in the last 10,000 miles and its consumption is negligible during the 5,000 mile intervals.

Another suggestion would be to call Mobil's 1-800 662-4525 and ask them questions/express concerns. The list of automobile manufacturers endorsing the use of Mobil 1 synthetic oil in their product offerings might be another source of opinion. On these shores, open the hood of any recent year Corvette, V-8 Mustang, Viper and you will see the Mobil 1 applique in a conspicuous place. Besides other German marques (BMW & Porsche), I recently attended a car show south of Houston and noticed a $317K 2005 Maybach 57 had the Mobil 1 decal on the sheet metal above the radiator indicating this is the preferred oil for this engine. Works for me ...

[Benzbug]

Thanks everybody for the input.
The transmission on my 94 S320 is a 722.5 which calls for Dextron fluid, so I think I should be OK using Mobil ATF since this is the case.
Any thoughts or confirmations? :-)

[nenad16]

Originally Posted by Benzbug

Thanks everybody for the input.
The transmission on my 94 S320 is a 722.5 which calls for Dextron fluid, so I think I should be OK using Mobil ATF since this is the case.
Any thoughts or confirmations? :-)

yes, you can use other ATF's in you trans, and I would highly recommend trying Redline Synthetic ATF or B&M Trick Shift.

nenad