I'm always open to suggestions as to the method of positively confirming the turbo seals. My only solution is the removal of the breather hose and stick it in a bucket. If the intake still remains soaked with oil, then the turbo seals are the culprit. If the bucket fills up, then the turbo seals are fine.

You can rebuild one of them for under $100. I'm going to do the '86 and see if it reduces the oil consumption........currently 1 quart every 2K..........but.........interestingly..........the consumption has very nearly stopped near the end of the 5K interval. It will start again with a vengeance after the oil is changed.

Brian, you planning on doing all seals and bearings or just compressor side? I never figured out how to get down into the turbine without some sort of special tool (on a Garrett) and figured I'd just do the first bearing and seal as shaft has no play and I was most suspect of the carbon gas seal. Worked out fine.

I had good success with these guys for the kit and individual parts : www.dieselusa.com . Hattip to blueranger for the source

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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)

I've got the KKK but I certainly want to take the entire unit apart. I've got the capability to finely balance the rotor and will likely do so.

I've been troubleshooting the massive oil consumption problem, as well. I've rebuilt the turbo, but when I first put it back together, the car used even more oil. So I took the turbo off of an 87 OM603 and interchanged the exhaust connections so that it would fit the 3.5 OM603 engine. I too didn't want to pay $500.00 plus the 5 hours and still have the same problem.

I also replaced the valve seals and corrected the problem I found where the seals had been placed in order of: intake seal, then exhaust seal, in the same sequence on all six cylinders, rather than being inserted with an intake seal on an intake valve and an exhaust seal on an exhaust valve in ORDER of the valves arrangement, i.e. (ext. int. int. ext. ext. int. int. ext. ext. int. int. ext.)

I also did a preliminary compression check, but I used a fabricated adapter that didn't fully hold the pressure, but gave me an indication that the #1 cylinder was lower than the rest of the cylinders (225, 250, 250, 250, 250, 250).

Since the car was drinking oil, when I first got it, I decided to use regular Havoline 10W-40 oil, since per Mercedes specs, any SAE appoved oil rated for the varying temperatures of the region the car is to be operated in, is acceptable. I'm going to change to Rotella 15W-40 and see will that decrease the oil consumption, since the valve seals had to contribute a little to the oil consumption problem, if not be the sole source of the problem.

Has anybody had any success eliminating the oil consumption problem, without having to fix the bottom of the engine? I read where Steve, at his shop, found some head gasket issues that contributed to the oil consumption. And I want to be absolute sure that a bent rod is the problem before I tear the engine down to correct it. Also, this engine had been rebuilt at about 105,000 miles and it now has 178,000 and hopefully the rebuilders didn't put it back together with a bent rod and ovaled out cylinders. But nothing hardly surprises me anymore as far as it goes about these cars.

Anyway, even with the oil consumption, I don't plan on getting rid of this car any time soon. I've put over 15,000 miles on it in seven months and have corrected a ton of problems that were wrong with the car before I got it, but haven't solved the oil consumption problem just yet. The car runs great. It's just an inconvenience having to constantly open the hood and check the oil on a top of the line MERCEDES BENZ car all of the time, when my neighbor's Lexus hood has never been opened, that I've seen.

BenzDiesel

I believe you are in a catch-22 there. It's not possible to be absolutely sure of a bent connecting rod unless you remove the head and check the piston heights. If you've rebuilt the turbo and have also confirmed that the oil consumption is not coming from blowby (I doubt it), then you've done all you can do without removing the head.

If you are able to perform an accurate compression test, however, a cylinder with a bent connecting rod will be lower than the remaining five, however, it's still not defacto evidence of a bent rod. You may simply have a bad head gasket which allows oil to get into the #1 cylinder via the chain gallery.

Your next step is to remove the head. All your answers will be there.

I'm well aware of all that you have said. I'm just not in a big rush to tear down the engine. If the car continues to drink oil after running Rotella on my next oil change, then I'll have to plan on rebuilding the engine next spring some time. As I said, I don't like adding oil all of the time in this big Mercedes, but as long as the car performs like it does, I'll keep adding the oil.

BenzDiesel

I know the feeling. I did the head on the SD last fall and it turned into quite the endeavor........nearly four months........due to various obstacles along the way.

But, the end result was worth it. No "get it done today" rush scenarios that result in a screwup. The 617 runs perfectly and it gets 29-30 mpg routinely and starts at 12°F. in one second.

I would have never done it if I had to finish it in one or two weekends.

It took me about three years to recover from that cracked head issue on my first OM603, but I eventually recovered. That's why I want to be absolute certain before I remove the head and possibly have to go into the block on this engine. Anyway, whatever the problem is, I'll get it and when this thing stops drinking oil, it will be one fine automobile. But in the mean time, it's going to have to be a "big, smoking Mercedes Benz" because I'm not about to ease up on it. And if somebody don't like smoke, they will have to pass me.

BenzDiesel

You've never seen smoke like I had with the '87. It was consuming oil at a rate of one quart every 100 miles.

Coming off a dead stop would fog out the entire road.

A completely trashed turbo will do that to you.

Did you do this with the head on the engine? If so did you use special tools or can it be done with hand tools?

Thanks,
Sixto
93 300SD

Did the turbo repair solve your problem? I'm still leaving the turbo option open as being a cause for my oil consumption, a little. I had problems with that carbon seal in the first turbo and just took the top of a T3, which didn't have a carbon seal, but another design and put it back together. That's when the car really dranked oil. That's when I took the spare turbo and put it into action. Oil consumption is reduced, but for me, adding oil to a Mercedes Benz, is not something that I want to keep doing. That's part of why I got Mercedes Benz in the first place (few break downs, durability, and not having to open the hood all of the time).

BenzDiesel

I've got bad news and worse news. First, the OM603 has the same sequence of int/exh for all 6 cylinders... it doesn't alternate like the OM617 engine. See photo below. So if you put them in some alternating order, you have the wrong seals on some valves, and the stem diameters are different.

Second, you have the 3.5L engine, which is infamous for the exact problem you describe, and 9 times out of 10 it will NOT be something as simple as a bad turbo seal or failed head gasket. The only way to check the rods is to pull the head and measure piston protrusion (or, pull all the rods and measure them.) A compression test will give you a vague idea, and if #1 is low, that still means you need to pull the head to check for the possibility of a failed gasket between #1 and the timing cavity (which is not common but does happen.)

On a side note, any xW-40 or xW-50 oil is fine, but make sure it is diesel rated (Cx)... a LOT of oils these days are not, they are only rated for gas engines (Sx). The Sx rated oils can't suspend the soot load produced by these engines.

I fabricated all the tools that I needed. I used air to hold the valves. And was very lucky "TWO TIMES", because I had two valves to drop, the first as a result of the worn seal not having enough tension to hold the valve before I figured out how to fabricate an adapter to get the air to hold the valves. I was just fortunate enough that I worked on #1 and then on #6, where both pistons were up on TDC. I was lucky that the valve didn't tilt over when it fell into the block on #6 and used a magnet to pull it back up. Now on that #2 valve that dropped, it dropped after I had already put on the new valve seal and the tension of the new seal kept the valve from falling all the way through, and gave me just enough hold to get the magnet to pull it back up. Talking about stressful, it really was because if #2 had fallen into the block, I would have had to take the head off, on the spot, since #2 was not at TDC.

BenzDiesel

I did this with the head on the engine. You need the Mercedes valve spring tools. The aftermarket tools cost about $200 or so, and you need to be careful not to score the hydraulic lifter bores. With the piston at TDC, the valves will rest on the piston crown, but if you screw up, you'll have to pull the head to retrieve the lost valve. See photos below.

The factory valve sprince tools are very, very cool, they automatically retrieve & install the keepers, and have a nylon (?) body that goes into the lifter bore to avoid any damage. Very slick, but also about $750 for the set. Wish I had those back when I did this job!

Factory valve spring tool set (works for almost all OM6xx and M1xx engines) photos here:
http://www.w124performance.com/images/tools/
(there is also a photo of the aftermarket tools.)

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I'm going to get in trouble for this but German cars are known for oil consumption. MBs that don't burn oil are seemingly exceptions than the rule. When you buy a new BMW some dealers give you a compliementary first quart of oil. Is this perception an old wives' tale?

Admittedly the 95 S420 didn't burn any oil over the couple of years I had it.

The Toyota Previa is the only Japanese car I know of with a low engine oil warning light, and only because it's inconvenient to get to the dipstick. It has a 2 quart oil reservoir under the hood that refills the engine under the car as necessary. Interesting set-up. I wish I could fit it in my SD for long trips for extra security. Maybe I can dump the MAF to fit a reservoir.

Sixto
93 300SD