Oil is tested and verified with soot content. At the time Mercedes was making these cars, the best oils could only handle 1 or 2 % soot. Many diesel synthetics can now handle 6% and a few 7.5% soot, and still meet the requirements.

So until your oil hits the maximum soot carrying capacity of the oil, soot is not the limiting factor.

4.5% soot level in 10,000 miles is very high. I would bet that's a car that's getting a lot of very low cetane fuel, or a lot of city driving, or has compression issues.

With fuel that meets Mercedes spec and mostly highway driving, 2 to 3% soot is much more likely in 10 kmiles.

10kmile diesel synthetic oil change intervals is a no brainer in these cars, and if you know what you're doing, a lot higher is no problemo. And that's not opinion, it's fact backed with lots of data.

Joe

We're still awaiting the data.

Good luck with your engine.

I did post data on the other topic that you shut down. I'll repeat it here again....


1984 Mercedes Benz 300D
3/18/04 to 8/2/04
2324 miles on sample
157168 miles on unit
Pennzoil Long Life 15W-40 CI-4
Mann Filter
3/4 quart top off
5 oz. of Soyshield in each tank of polished fuel

Fe 10
Cr 0
Pb 1
Cu 2
Sn 0
Al 4
Si 7
Na 0
Mo 48
K 0

Viscosity at 100C. 13.6
Water 0.2
Soot 0.3
Fuel 0
Glycol 0

Oxid 1.7
Nirt 0
SAE 43
TBN 9.6

Analysis by Oilguard

It shows soot at 0.3 for 2300 miles. That's 1% in 7500, roughly. So if you can go to 6% soot, which many synthetic diesel oils can do, that's 45,000 miles before the soot maxs out and the oil can no longer meet spec.

Even at 15,000 miles, thats only 2% soot. Now you will note he's using polished fuel. That does make a difference but at 15,000 you still have a huge engineering margin.

Maybe now you can see what I'm trying to tell you.

I can't figure out if you're waiting for data from my cars. You won't get it. I don't need that data. I can extrapolate from other data and base my actions on their results. No, it's not perfect....but it doesn't have to be.

I don't have to jump off a bridge to know it is going to kill me.

Joe

Your problem is that the data from some other OM617 may or may not apply to your own engine. These engines vary widely in the amount of soot produced and are heavily dependent on the type of driving and the condition of the engine. So, until you have the data for your own engine, you can't draw any conclusions.

And, for your information, the generally accepted limit for soot is 2%. As we mentioned to you on the other thread, you can run the oil until the soot reaches 7.5% if you like. It's your engine. However, you have no data whatsoever to support the wear levels in an OM 617 with 7.5% soot, so all of your statements are simply BS.

I've got the data for this OM617 and it shows that the soot levels are approaching 1.7% when the engine reaches 8K miles. I don't wish to run the engine right up to the 2% limit. But, hey, that's just me.

As I told you on the other thread, it's your engine.........do what you want.

I go 10K on my two 240s using Amsoil 15/40. The "79" had a small oil leak from the rear main seal (I screwed up installing the seal) Now it has almost completely disappeared.

I believe Delo 400 is, hands down, the best "dino" oil out there. I think all the tug outfits I have worked for use it.

__________________


1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

I am with Larry on this one...oil and filter are the cheapest maintenance that one does on these very expensive and complex machines. I for one will stick with the 3K oil and filter...besides, it gives me an opportunity to get into the garage and under my cars.

Antonino

'78 Alfa Spider Veloce
Mustang 289 Coupe
'91 300 CE

Brian,

Seriously, you don't understand the oil spec. The oil meets its lubrication spec carrying 7.5% soot, or 6% or whatever they spec it at. It is tested at that soot level in a test stand. Soot causes problems when it clumps up. These oil have additives that keep that from happenning.

2% soot was the old ballpark figure that the oil was good to. There is NO engine spec that says 2% soot. They just knew at the time that if you hit 2% soot, the oil is going to give up and that's bad for the engine. Those days are gone.

Joe

I don't need to go 15K miles between oil changes to know it's not good for my engine.

Craig,

Well it's 2006. You can live in 1974, or 1984, but that doesn't change the fact that it's 2006.

15,000 miles on synthetic diesel oil, with a few conditions, is a lot less harmful than actually changing your oil more often.

Have you ever heard of Maintenance Induced Failure (MIF). I'm a engineer in the aircraft world. MIF is a serious issue there. MIF is also a serious issue when doing oil changes. Make a mistake and you might...might starve the engine for oil. I know the chances are very small if you are careful, but it does happen.

I know from personal experience and 25 years of data in the airplane business, that every time you do a maintenance action, there is a small, but non-zero chance of a terrible mistake.

With autos, you might lose an engine. In the airplane biz, you might lose 450 passengers and crew.

Joe

Although this is my first <10liter diesel, I'm running mine on Delvac 1/6-mo changes. It is not as good as Redline's syn diesel oil which is a polyolester stock, but it isn't as expensive either. From memory I believe it is around 10.5TBN, RedLine and Amsoil's Heavy Duty Diesel and Marine are 14TBN and 12TBN respectively I believe, I prefer to stick with 12 or better for an annual-change oil.

Holland Motor Express used to run their OTR trucks with Delvac 1, did a minor at 250,000miles at which time the oil was changed. This was about 2years' mileage. The filters were changed regularly (and to be honest Detroit 2-strokers pretty much changed oil as they ran), The result was less un-scheduled downtime (break downs), reduced oil consumption/cost, and reduced fuel consumption. I don't know what they do now, I no longer work with them.

The additive package does diminish even without use. You can not store an engine indefinately with old oil, the oil will break down with time. Regardless of the oil's brand and pedigree you will eventually need to either change it or re-refine it. There are filters for bigger engines (Lubrifiner?) that claim to extend the oil's life, but they cost more than the oil.

Not all "synthetic" oils are the same. The word "synthetic" can now be used on any oil regardless of basestock, provided it has been "cracked" a certain number of times, as it is then considered synthetic. Mobil 1 used to use a synthetic basestock, I believe that the only ones that do now are the Delvac 1 and the "Mobil 1 Extended" product. The regular Mobil 1 I'm told is a petrol basestock as are many other oils labeled "synthetic". Remember when "all natural" meant something also?

I will NEVER use a multi-viscosity dinosaur oil. To simplify, a 10W-40 dinosaur oil is typically a 10weight oil, with viscosity modifiers added to keep the oil thicker at higher temps and thus gain the rating 10W-40. These short-chain polymers are fragile, don't protect well in high-shear applications such as camshaft lobes, and break down. You're basically protecting your engine with SAE10 oil.

Synthetics earn their multi-viscosity ratings (at least in part) by naturally not thinning as much at higher temps nor thickening as much at lower temps. Mobil 1 5W-30 was (originally) produced with no viscosity modifiers, so viscosity breakdown and high-shear failure were not a problem.

One poster says he starts the car and lets it idle for 10minutes, most of us consider the carbon buildup under the top ring to be bad, and idling is a major contributor. It also creates lots of condesation and un-burned fuel in the crankcase, your best bet is to start the car, drive it gently until the temp is reading on the gauge. Any diesel manual I've read specifies not idling the engine for extended periods or for warm-up.

Another myth is the oil leak thing. Back when I recieved Roundel (sp?) I remember M-B's official stance was that synthetic oil could cause a leak to become more evident as the oil doesn't thicken as much as dino oil when the engine is cold, and therefore would continue to seep/leak. They continued by saying that if an engine "converted" to syn leaked more, just switch back at the next change or try part-synthetic. Simple enough. The myth started back in the mid-'70s when synthetic was new. We tried it because the arilines had switched all of their turbine stuff to synthetic, ... we had comparitive tests and data (compliments of the airline's lab) measuring metallic particles etc. in two premium dino oils plus Mobil 1 and Amsoil in our cars. The amount of metallic particles was vastly different between the synthetic and dino, only slightly better in the Amsoil than the Mobil 1, ... but I digress. Anyway, the myth: Oil in your engine reacts with rubber seals etc. with a finite and constant amount of swelling. You can see it on oil-soaked external rubber parts some times. This swelling of seals creates a certain position and interference fit between the seal and the part sealed (especially rotating parts). If a fluid is introduced that creates less swell, there is now a clearance between the worn-in seal and the mating surface.
Early synthetics didn't have the same swell characteristics and seals regressed, causing leaks. This was addressed with reformulations about 25years ago, but bad news travels faster than good news. Most synthetics have the same reactive/swell characteristics as the dino oils now, so they really don't cause leaks, they just don't stop leaking when they're cold.
Which is the next point: thick oil.

When you start your engine, especially in cold climates, the faster the oil pumps up to pressure the faster it can protect your engine. Starting your engine it has been said is the primary wear period of engines, it is also when the most contamination of oil occurs etc. If your oil is as thick as peanut-butter (as in a cold Michigan winter), it will not pump up quickly nor lubricate as well cold as a synthetic which is close to its normal viscosity when cold. Ditto for gear oils etc.

I also hate the dry-run of a fresh oil change, when the air in the empty filter casing is pushed through the bearings and displaces the oil there, ... a case for not changing the oil too often?

Oil useage: Dino oils tend to burn more and evaporate more, suffer viscosity breakdown more quickly. Normally the dino oils burning and evaporating shows up as oil useage where the more stable synthetic oils stay in the crankcase better. If an engine burns less oil after converting to synthetic (typical) it didn't "heal" itself, it's just running an oil that doesn't burn as easily so more oil is returning to the crankcase.

I have been using synthetic oils in my vehicles for almost 30years now, have done plenty of spectro-analysis etc. in the early years. It is IMO superior to the dino oil, even after thousands of miles vs new dino oil, provided there aren't other problems. I prefer to run annual oil changes, change filters at factory-specified intervals, and have no internal engine problems and a really clean valve train. Good filters are important, very important, and knowing whether your vehicle and driving are compatible with extended drain intervals is key. My wife's gas van, ... short-haul driving and idling at the school, not an extended-drain candidate. In fact she gets Delvac 1 and Mobil 1 filter every 6k.

A couple of final points I consider important. Never never never never (did I say that enough) use any products/additives containing PTFE (Teflon is a trademark so it might be listed as the generic PTFE). PTFE's breakdown temperature is lower than the temperature at which diesel fuel burns, ... PTFE coating the cylinder walls, "suck-squish-boom-go", burned PTFE is a good way IMO to make your rings stick in the piston and score your cylinder walls (as is carbon from extended idling). In fact I personally feel that buying a premium diesel oil (whether syn or non-syn) gives you a good additive package and really doesn't need any of the snake-oil additives (Slick 50 comes to mind) and unless you really understand engine oil you can very well make it worse by adding some of the off-the-shelf products.

That having been said, there are good oil and fuel additives, but good premium oil and premium filters (none of that Fram crap for my cars) will make them last a long time. Extended drain? For some good, for others bad. I don't suggest that anyone run oil change intervals that make them uncomfortable, changing the oil more often is pretty cheap maintenance really as is putting in good oil and filters.

Now how about engine coolant? Anyone? Is cavitation pitting a problem in these engines?

- Jeff Miller
'87 190DT

Yes, Craig, it's a very difficult task to change your own oil and you might make a serious mistake and it will cost you your engine.........so be very wary of doing these oil changes........in fact.......maybe you wish to consider going 50K miles between oil changes to minimize this obvious risk??

Thanks Brian,

Now do I put in the new oil before or after I replace the drain plug?

Excellent post babymog.

I think maybe the "change it hot and often" crowd actually derives some type of psychological therapy from this ritual. And it seems to be more habit forming than smoking.

Maybe I should develop a 10 step program....

Joe

Gee.......maybe I better go look it up in a procedure......don't want to make a mistake and cause a "maintenance induced failure".

Brian,

I hate to agree with you, but from what I've seen so far, maybe you should.



Joe