Synthetic Fluids W140
 

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. :-)

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.

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

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 $$$).

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

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.

My $0.02
 

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 ...

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