marauder

Well, actually, I don't have any real facts -- I was hoping that you had some! Maybe you had heard it from a Mercedes tech or something who had heard it from some Mercedes engineer, etc. You may not have any adverse problems, but maybe better fuel economy? Lower emissions? Longer life? ... I don't really know for sure. It's just that I don't hear that weight being used very much when I hear talk about oils. So stick with what you're doing if you're happy with it! But I would ask around to see what some techs think.

V12BIGBODY

Well I really didn't want to say this because I thought you would disagree but this is what I heard. Remember my old MB tech that told me to use 20/50 on higher milage cars. He said that 20/50 weight is thicker than the regular weights. So when it sits and cools the oil gets thicker and stays on the upper engine parts so when you restart the car it's less likely to have a (dry start). Also that when the car is running the oil is a little thicker so it coats the engine better. I don't know if this is true or not but the guy was an old timer at Mannahattan MB and he sounded like he knew what he was talking about. So I went with it. I'm going to ask around about this. You love stirring it up now look you gave me more things to do ( just kidding) !!! I want to hear your opinion on this. Is there any truth to it?? At least 1 bit

patrick

The ability to stick to (upper) engine parts has nothing to do with the oil weight.

After a cold start 20W50 takes longer to reach the upper engine parts than 10W40.

But Mercedes engines are strong so this is the reason that you have not noticed anything yet. However, maybe a good mechanic could for example hear something not right but that you do not?

New Mercedes engines are coming. The oils for it have MB specification according to page 229.5 (Mercedes lubricant prescriptions). If you should put your 20W50 in them, you will definitely get problems.

Patrick

marauder

Well, with a 20W-50 oil, it should be harder to start the car when it's cold, but you don't seem to be having problems that. The operating viscosity of 50 is a bit high if it's recommended that it's 40. If it's too high, common problems are engine wear, oil breakdown, and deposits, but you don't seem to be suffering from those problems. Perhaps your engines have been more tolerant if you're not seeing such problems.

Regarding the cold start question and the ability for thicker oil to stay in the engine instead of coming into the oil pan after being shut off: I think it's a valid point, but I wonder how long it's going to take for the oil to drain. The point is that if you can keep the oil up in the engine where it needs to be when you start the car, you'll minimize wear on a cold start. But if the high viscosity oil keeps it up there for 3 hours and the low viscosity oil keeps it there for 1 hour, and you only start the car after parking it for 8 hours, it doesn't matter which one. I'd say that it's an older adage that may have been more true in the past with huge oil capacities and lots of lubrication, but the tight running machines of today probably drain the oil out faster. That's my guess, though.

E55MKB

A good source of primer on automotive lubrication is

www.redlineoil.com
http://www.waynesgarage.com/docs/synthetic_oils.htm

As usual take the informations with a grain of salt.

E55MKB

Patrick said:

"The ability to stick to (upper) engine parts has nothing to do with the oil weight. "

With regard to what Patrick is saying, here is an article which mention the role of polarity (charge) of the lubricant in the "stick" to the metal parts.


http://www.scooterhelp.com/genmaintain/2stroke.oil.html


HTH,

levelr123g

i have always used amsoil in all my cars. my acura which i sold to buy my mb used amsoil since day 1 and i never had any engine failure. after 11 years and 300000+ miles im happy to say its till going strong. if anyone is interested in this you can go to my home page at www.syntheticoil.netfirms.com or you can email me at nov0798@peoplepc.com. check it out at www.amsoil.com. i currently run 0-30 in my car and have had it in there since the 2nd day i owned it. i also use the series 2000 75-90 gear lube in my differential.

star

[QUOTE]Originally posted by V12BIGBODY Most of the time I change my own oil and do basic mantainace myself at 3k miles my oil is fairly black [B][QUOTE]Originally posted by V12BIGBODY Most of the time I change my own oil and do basic mantainace myself at 3k miles my oil is fairly black


I dont want to enter an aguement here, but why is your oil black after only 3000 miles?
Ihave done 5000 miles in my E280 with 114k on it and my oil is just starting to change color.

E55MKB

Star:

A lot of factors affect the quality of the oil during use not to mention the quality of the oil at the beginning of use.

Conditions of the engine and especially the mode of operation of the engine. Lot of stop and go traffic and/or lot of short distance use (in which does not really allow the engine to achieve operating temperature) will really affect the quality of the engine oil. Sometimes the coolant water already achieved operating temp (thermostat fully open) but the oil is still at a lower temperature. These factors really contributes to sludge formation.

When piston rings start to get loose thereby allowing more combustion by-product to "blow-by" to the underside of the piston (hence goes to the oil)

star

E55MKB,

I still cant understand how V12BIGBODY with a 99 ML and a 96 S600 have black oil after only 3000 miles, surely such newish cars should have cleaner engines seeing that he changes the oil every 3000 miles?
I used to own a Capri and when I got it the oil was black so I when I changed it I used engine flush and that oil stayed clear for 5000 miles till I changed it.
What I'm trying to say is something must be wrong with either Bigbody's engines or his Quaker oil?

E55MKB

Star;

Even newer engine if driven a lot of short distance with the oil not achieving normal operating temperature will suffer from sludge formation. It is the unburned fuel that goes into the oil that did not get a chance to evaporate (not enough heat) that will accelerate the sludge formation.

SpartonMB

I spoke directly with Mobil Lube engineers shortly after the 0w synthetics came out, and they were very high on the oil's capability. They only mentioned Mobil 1 0w-30 at the time, so the 0w-40 is new to me.

In addition to Porsche and MB factory fills, please note that Corvette has been Mobil 1 factory fill, since the early 90's, when their very low production, high output, aluminum block engines suffered broken cam shaft gears, using mineral oil. These engines were built by Mercury marine, because they had much experience with aluminum block engines, building high power outboard motors.

Their plant was/is in Wisconsin and during the winters, temps would get down to 15-20 below zero. When the Corvettes were started in such cold weather, the stiffness of the mineral oil, coupled with lack of lubrication reaching some cam bearings, caused high rotation resistance in the cams, overloading the cam gears, damaging them. The cure was synthetic Mobil 1, because it flows so well at cold temperatures, (plus they opened up one bearing, which was a little tight). Also, the Mobil 1 provided high protection at normal and high engine temperatures.

I have run Mobil 1 for about 6 years, with which I believe are good results. If you read Consumers Reports, they report no difference in performance, i.e. lubrication and wear, compared to mineral oil. However, their tests stopped at 60,000 miles- no challege at all. There is a noticeable difference at 150-200,000 miles, if synthetic oil has been utilized at 15,000 mile changes. I have seen parts pulled down, in which there was no discernible wear! Taxi cab companies can run 400-500,000 miles on their vehicles. Usually the trannies go, before the engines.

I have run close to 200, 000 miles on several vehicles, including 190,000 miles on a Buick Wagon w/350 ci V8, and follow the Mobil engineer recommendation for oil changes:
Change the filter at 5,000 miles, using Mobil 1 high filtration filter,
Change the filter twice at 5,000, and 10,000 miles,
Change both the oil and the filter at 15,000 miles.

This V8 Buick only "uses" about a 1/2 at oil, at 5,000 miles with 190k miles.

I also have a Buick Ultra with belt powered roots-type supercharger and the blower runs synthetic oil, that only need be checked at 30,000 miles. I am told by dealers that buy at auctions that these supercharged 3.8L V6 engines are legendary for long life. E.g. 180,000 miles and up.

I have had a number of cars with oil pressure gauges, including MG, Mercedes, Olds Toronado, and Buicks. I have found dramatic differences in oil pressure, as the oil "ages", i.e. at miles accumulate, based on which brand, type, and weight of oil. In one case, I thought I had a damaged engine, because the oil pressure dropped off so badly. When changed to Mobil oil, the oil pressure returned to normal.

Something you won't do, but I have, is to observe an old push-rod engine start cold with the valve covers removed. You would be astonished as to how long the engine must warm up, before oil flows to all lubrication points. This can be up to 1 or 2 minutes, in weather down around 35-40 degrees F. During this time, only the old oil film is lubricating. With synthetic oil, oil pressure builds and flows to all points within seconds of starting cold.

Why synthetics and benefits:
1) Very close to instant lubrication at cold start, esp. in very cold weather, e.g. below zero: no loss of lubrication, for the first 1 or 2 minutes, as occurs with mineral oil.
2) Good protection, when under heat load: no breakdown and adverse wear.
3) Next to no oxidation (sludge) over time: no plugged passages and loss of lube. Please note that Lexus had a technical bulletin published, because mineral oil was plugging a small oil passage, causing loss of lube and damage to some bearings.
4) Better control of acids and contaminants: less long term damage to metal parts, esp. bearings.
5) Better long term condition of seals, which can oxidize and dry out with mineral oil.

Observations: If you plan to buy new and unload your vehicle by 60,000 miles, then feel free to use mineral oil. You won't care- the next guy lives with it.

But, if you retain your vehicles for long periods or for higher miles, you can't go wrong with synthetic oils. I believe that in very tight tolerance engines, esp. such as MB, the benefits would be very high.

Quincy Leslie