At 11pm the oil level in #1 is at 46+mm and #2 is at 43mm. So 2mm drop in #1 and imperceptible drop in #2, imprecise methods notwithstanding.

I expect the ring gap is biggest when cold and the ring about closes when hot.

Doesn't the oil control ring set just about seal the combustion chamber in a static and unpressurized situation?

Sixto
93 300SD

No noticeable loss of coolant. I was hypothesizing at the end of the post that had it been leaking coolant into the cylinder it would have had hours to leak past the rings, and, if it did that, it would have started to leave evidence on the dipstick and oil cap that there was a significanct amount of water in the oil. But no, my car was merely swallowing a quart of oil every 100 miles all of the sudden. It had always used about a quart every 5000 miles before and then it developed a growing thirst. In a matter of a few months and maybe 3500 miles it was consuming a quart in less than a tank of fuel. But I never had a coolant consumption/loss issue during this episode. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

tom my take is that time dont get factored in, its the % of loss that is monitored,and if the total ring loss is 20% and you divide your number of cylinders into 20 then you should have a balance of 96-97.
brian you could have used ups nda early delivery,lol good one.
piston to cyl wall clearance,manual states .0007 in to .0011 in clearance and that is measured at the wide part of the skirt,the pistons are oval shaped ,this measurement is taken at 90 deg from the wrist pin, at the wrist pin side you can add at least .2 inches of clearance(never really measured that side,will do next time for clarity).i have read some about the pistons design of oval to round as the piston heats up so am to believe that the clearance is maintained.if one considers the low side tolerance on ring gap(.012 in and the diameter of the piston it couldnt expand more than .003 in else the rings would break)
i am a firm beliver in heating the engine with the 115 block heater when possible and not let one set and warm up before driving,get that cylinder sealed to its max asap.
larry perkins

Now if the rod had the same circumference as the piston and was made out of steel, then I would say no, in agreement with you, Sixto. But a relatively "thin" rod, and knowing Mercedes; the rod COULD BE made out some kind of heavy duty plastic or some new kind of other metal and it be connected in the center of an aluminum piston; I can easily see the rod being bent by the force of the starter. But DEFINITELY being bent by the upward pressures applied during the compression stroke as the solidified carbon is compacted on the exhaust valve. After all, in my opinion, it’s not like the rod breaks or the rod's bend or the piston's tilt in the cylinder happens all at once. It is a gradual process, I think. Which brings me to this question, if the rods aren't causing the tilt, then could it be the aluminum PISTONS bend, (maybe at the wrist pin connections or along it's axis parallel to the piston's center) causing the tilt?

Anyway, my oil consumption is not where I want it to be now, but the motor is definitely drinking less oil and the car is smoking significantly less. I'm at about 850 miles and have added only four quarts, thus far and the yellow warning light indicating low oil level, hasn't come on yet. I will take an average of miles per quart of oil consumed when the yellow light comes on.

BenzDiesel

Can you explain?

Four quarts in 850 miles doesn't make sense??

Oil light has not come on??

Well, about the 850 miles, if you know the oil consumption in these Mercedes Benz cars, with the 3.5 engines; then you would know that you CAN, as some have confirmed, possibly get as little as 400 miles on four quarts of oil. On my Mercedes, when the oil level gets to the bottom red mark on the dip stick, a yellow caution light on the instument cluster will come on to let you know you need to add some more oil and this, I am thankful for Mercedes adding this little oil light warning system, although I really wished there was no need for gadgets such as this on a premium series car. So, rather than checking and continuously opening the hood, which I don't like to keep doing every day or so, I'm going to go until the yellow light comes on, which means it is time to add two more quarts. Since you don't really know what I'm talking about based on your questions; you can count it as a blessing and rest assured that you don't have a bent rod, or bent piston or too much carbon or blown head gasket or bad egr or bad turbo or coolant/oil leaking into the cylinder or whatever is causing these engines to respond in the manner that SOME do,....yet. Anyway, I had expected the car to continue to consume oil at the beginning of the accumulation of the miles for a period of time right after the work that I did to the car. And I base this on the same premise that most rebuilders of engines take and that is; it sometimes take a good many miles before symptoms go away and for the engine to completely seal all of the components that relate to the oil consumption issues. Hopefully, everything will settle down and the car will stop drinking the oil and just consume a little oil or relative small quantity of oil over time, like regular oil consuming cars do (a quart every 1500 miles or so), which would make me mostly satisfied, since the car has such a great ride, even as it be drinking the oil. If it continues to smoke and consume oil, I am going to throw in the Billet Rods into the mix, if it is determined definitively that rod bending is the result of poor quality in the manufacturing process of the rods in the 3.5 engines that were imported into the United States of America by Mercedes Benz Motors and it is FOUND that the bent rods IS the culprit and source for the problem of EXCESSIVE oil consumption. I wonder was a strike going on at the factory, when these engines were built in the early 90’s?

BenzDiesel

Clearly, you've ignored my signature, or you wouldn't be making such ridiculous statements.

My original question concerned the use of four quarts of oil within 800 miles. The oil light would have been illuminated at the point where the engine requires 1.5 quarts.

So, the question remains. If you've added four quarts of oil to the engine within 800 miles of driving, why has the light remained extinguished? Have you consistently added oil before the oil reached the lower mark? If so, this could be part of your problem. The 603 seems to consume oil based upon how full the crankcase is. My '86 had cut it's consumption dramatically if I leave the oil level right at the low mark.

must i send my oil in like brian to get the test result sixto?
larry perkins

sixto

what made you think in the first place that there was a potential bent rod? Oil consumption I assume?

I did the same oil in the cylinder test you did with less precision (I eyeballed). Left it in there for a few weeks with no noticeable change in levels. I'd like to think this good evidence that the rods are still ok, but I doubt it's conclusive, especially since I did it while the motor was in the car so due to engine tilt couldn't check all the way around.

Oil consumption on mine before turbo rebuild was about 1qt every oil change or approx. 3000 miles. Turbo was definitely eating some of that and I drive 80-85mph which accounts for some too.

__________________
1982 300TD 210K miles ("The Replacement" aka "The Anvil") - SOLD
1979 300SD 245K miles (never ending project)
2007 Pinarello F3:13
1995 Ducati 916 (SOLD, sniff)
1999 Ducati 900SSie (SOLD)

My car in this thread is not an 86 603. And, I don't buy that belief that "no oil consumption when the level on the dip stick is low, but if filled to the proper levels, then the car will consume oil". The engine is going to consume oil or it isn't, unless something is wrong with the dip stick itself, which causes you to overfill the crankcase if you go by "your" dipstick and once the excess of oil is burned off, indicating a FULL crankcase, but showing low on your dip stick"; is the only way I see the oil consumption stabilizing to zero: that is the only way I could buy that, using no oil once the level got low. It's not just a Mercedes Benz engine, any engine will do what it was designed to do, (not burn oil) IF the sources of the problem can correctly be diagnosed. I'm not an expert, but I do know what I know about my car and know what I want the end results to be, when I finish solving the problem (run good and burn moderate or burn no oil at all). And, I would never ask you a question if I already knew the answer to the question, just to be asking you a question; and then jump on you if I did't like your answer to the question that you already knew the answer to. But, for the benefit of no argument, I will explain again. I have put in four quarts TOTAL and have driven this car 850 miles. So that means that if the yellow light will come on when I'm two quarts low, then that would make me have added oil ONCE, right? What's important to me is to know how many miles I will get in these four quarts of oil. With the long run objective of determining when or IF the oil consumption will begin to stabilize. And then measure those figures against what I knew it was doing BEFORE I removed the head.

BenzDiesel

Sorry to tell you that your observation is not correct for the majority of the members on the forum. With the oil right at the full mark, the engine will consume it faster than if it's at the low mark. I never said that the consumption ceases. It simply is reduced. The fact that you've got 603.970 engine is a moot point. If it's common to the 603 series engines, it's going to manifest itself in that engine as well.

If I knew why the oil light never illuminated, even though you added 4 quarts of oil, then I wouldn't have asked the question.

If you added oil at the point where the light came on, and you added two quarts to bring it up to the full mark, and only added oil once, then how do you get to the total of four quarts?

Seems like your data is flawed or your math skills are weak.

just a word of caution,the low oil indicator float switch is not fool proof especially if you have loose parts swirling around in your oil pan as the 4 cars that i have completely taken apart had. matter of fact i will bet anyone that the one i bought today from michigan has bolts and washers loose in the oil pan.
man i hope you have a perfect engine,but the odds are you dont and the longer you wait to get to the problem the worse it will get. being in denial is a natural trait we all have,but it aint going to get you anywhere and i know i speak for myself--folks here try to help the .
larry perkins

about when the yellow light came on rather than when I was going to start taking that engine apart. And talking about dipstick measuring techniques, when I don't have to worry about that and my dipstick is just fine. Maybe I got a bad 3.5, but have a good 3.0, since I do know of Mercedes Benz products going the 5000 to 6500 miles between oil changes WITHOUT using ANY oil.

Anyway, what is so hard about understanding that I have added four quarts TOTAL and have gone 850 miles and am waiting to see how long I can go before the light comes on to let me know that I am still or maybe NOT (excessively), consuming oil? I'm not going to get into a "TECHNICAL" conversation with you trying to add up how to get four quarts of oil in the crankcase by adding oil only ONCE, since I started driving the car, since the work was done. Trust me, if you have read this thread from the beginning, then you would know the answer. But that isn't the issue. The issue for me is STILL what it is. How fast is the car consuming oil?

BenzDiesel

talking about "IS" causing my OIL CONSUMPTION? The odds of me NOT having a perfect engine??? Larry, that is an understatement. By the way, what are you going to do with all of those 3.5 engines that you have rebuilt? Do you have any "extra" un-bent rods sitting around somewhere that you want to get rid of?

BenzDiesel

What's so hard to understand is the fact that you added two quarts of oil, on one occasion, by your own statements, when the light came on, and, somehow, this equates to four quarts of oil.

I'm quite sure that you don't wish to get into a technical discussion with me, because your argument is nonsensical.

Trust me, I have read this thread from beginning to end, and the data is not apparent in any post of yours.