a good engine,can't believe it.
 

I tried to find something wrong with the diesel engine,made for 1998 and 99 E Class in the U.S. guess what nothing,but found all sorts of high performance parts for it.I did not know it was a M 104 block,with different heavier parts.
So how come Mercedes could do that,when GM took a 350 block and converted to diesel nothing but failures.I did not know too the E Class engines are indirect diesels too.

I have to agree with you; the mid to late 90s Mercedes were solid as a rock in terms of comfort and performance. Are you a fan of the newer Diesels? Thanks for sharing oldsinner111 !


-Dmitry

Ugh..

Chevy did NOT turn a 350 block into a diesel...

GM sent the dimensions of the BOP big block to detroit diesel and had them design a diesel motor that fit in the chassis...

Unfortunately, the BOP big block uses 4 bolts per cylinder, and couldnt handle the pressures of the 22to1 compression diesel...

Mercedes never under designed their motors... tank production from day one...

Block and crank in the diesels were common between gas and diesel at least back to 1962 when I had a 190c gasser.

The lower end on a benz is always rugged.;)

I'm sure I'll get flamed for this, but Mercedes isn't without fault. Let's not forget the cracked 14 heads on the 603's and the oil control and rod bending issues of the later 3.5L 603. Even with those issues, they seem to be pretty tank-like engines.

The 603 in my SDL is original to the car, and despite looking gunky on the outside and having clogged manifolds, the inside of it still looked nearly factory fresh after 30 years of abuse and neglect.

Just wish the resistance to rust on my 98 was as good as its engine....:(

Right on the money Shertex.
My 99 300D Turbo has 200K miles and runs like a clock with power and smoothness. But the rust has eaten the 4 fenders.
My # 2 daughter drives it now and doesn't complain. I spray paint over the rust in Rustolium Navy Blue every 3 months or so.
great car though.
I'm driving an ML 250 blutec now and it's another 3 levels up in all round improvement and evolution.
The direct injection and the 7 speed trans make it a game changer.
My 2 cents.
jz

Yeah baby! Go OM651!

I have the same love/hate for Mercedes' evolution that I have for Porsche's, ... they continue to improve, evolve, find a better solution. Every year or two brings another change, some small and some large, usually criticized by the traditionalists, but eventually it is proven to be ... BETTER.

Even in the mid-90s when MBUSA was chasing the effect of Lexus's prices, removing features like the headlamp switch, seat switches on the door, headlamp wipers, backup poles, ... the important stuff mostly stayed, and the next generation got even better.

Mercedes is constantly chasing its own reputation. Yes the early 602 and 603 heads had problems ON SOME CARS, maybe tied to the trap-ox which in many ways is the proof-of-concept for the modern SCR system, ... and fell short of the end of production 617s in reliability, but once those problems were found by way of a billion or so road miles and some abuse, the 60x showed itself to be everything the 617 was but with more power, efficiency, environmentally friendly, and quieter.

I have a feeling that the new OM654 will find itself in the same situation, with "big shoes to fill", and will eventually prove to be perfect for the evolving global market.

Put me down for a second-year production model though, not first.

Uhmm, oil control? I know about the heads and rods, but this is new for me!

Perhaps a poorly chosen phrase. The earlier head designs had an open oil gallery sealed by the head gasket that tended to fail and leak large amounts of oil into the #1 cylinder. The 3.5L was more likely to leak than the 3.0L due to the larger bore.

What vstech said. The M104 has 14 head bolts, the OM606 has 26! You don't just drill more holes in a block for more head bolts and call it a Diesel. Lots of shared dimensions to leverage rotational dynamic analysis but the 606 has pure Diesel DNA.

Sixto
83 300SD

I read-up a bit on the 1970's GM diesels. They actually worked the bugs out after a few years, but by then their reputation killed sales. GM has always been innovative, but uses buyers as their guinea pigs, a problem of corporate decision-making not engineering.

There are many engines that have a long legacy and are very rugged. The small-block Chevy V-8 in the Corvette, Camaro, and trucks is a direct descendant of of the famous 1957 Chevy V-8 and still uses push-rods. The Chrysler small-block was hardly changed from 1964 thru the Magnum engines (~2002), so much so that some bolt Magnum heads to a 1964 block and/or swap transmissions. Their replacements are high-tech, but showing issues. I think Ford is similar. But, perhaps on the pedestal is the Jeep straight six (4.0 L) with a block from the 1950's. Jeepsters mourned its recent departure.

As far as rugged M-B diesels (OM617), there seem to be many small things that can take one out. One of the biggest is the loss of a few tiny bearings in the vacuum pump can cause parts to slide into the timing chain and cause mass destruction. My 1985 CA engine failed at 330K miles from unknown causes. I found 3 of the 5 pistons missing chunks. A mis-aligned injector can burn a hole thru the pre-chamber and piston. People have found the camshaft towers broken. But, the biggest downside is that they can't be rebuilt affordably, due to lack of parts. If you can find a new piston, they cost $550 ea vs $80 for a set of 8 for a small-block Chevy. Add that many other parts for the vehicles are "not avail" or exorbitant and there isn't a bright future for driving these cars. At his first job out of college, my son asked about a 1990's BMW 8 cyl on craigslist for $4000 that look nice (other than dented door). I told him that car probably had negative value, assuming just a few typical neglect issues like "no charging" and "no AC". I see people do absurd things to keep Euro cars on the road, due to over-priced parts, like one neighbor bought junkyard motor mounts for a Volvo. No sane Chevy owner would put used rubber on their car, since it all costs $5 and always on the shelf.

Doing the oil cooler seals on my 642 has given me a new appreciation for it. It really is a well thought out system on top of the engine. It looks like total chaos when you first pull off that cover, but everything has a purpose.

The hoses and wire harnesses are all formed to fit back exactly where they came from. There are not a lot of odd brackets and fittings to keep track of. Really only one bracket in the V that ties the drivers side manifold, swirl flap motor, and turbo together, and sits on top of the plastic wire harness carrier.

There are some unavoidable interferences between parts that require you to remove something to get to something else, but the fasteners are all surprisingly easy to access. Even the ones in the back for the turbo.

Someone on the oil cooler thread complained about the different sized fasteners. This is true on the manifolds, there are 19 bolts and it seems there are about 5 different sizes. It's not like a 61x or 60x manifold, there are coolant passages in the intake manifold and it has to support all the EGR self choking system hardware. The thermostat and upper radiator hose connection are actually in the passenger side intake manifold.

The EGR is really what complicates things on the 642. If we didn't have the EGR it would be much simpler on top. There are 3 pieces to the system on a 642, as opposed to the valve on the 61x/60x engines that simply ties the intake and exhaust together. The 642 has the similar function valve, which opens a feed from the exhaust line, but after that, the exhaust gases go to an air to coolant heat exchanger, then to a mixing chamber in front of the engine, before being introduced to the post-turbo and intercooler intake air stream at the front of the manifolds.

Just to show some of the complexity, the intake air path traverses the length of the engine 3 times. First time through the filters, to the bat wing, to the turbo. Then down the big silver pipe to the intercooler. Out of the intercooler into the EGR mixing chamber where the cooled exhaust gases are introduced. Then into the front of the manifolds to be distributed to the cylinders.

To sum it up, having had 4 MB diesel engines, OM616, OM603, OM606, OM642, it is apparent how each one builds upon the predecessor. The day will come when I am going to have to replace the 3 that I have now. I think the engine technology will continue to improve and hopefully MB will keep building diesel - after the VW fiasco I am not so sure - as I really don't want a hybrid due to the high energy electricity involved. Digging into this 642 has given me a new appreciation for the engineering involved and given me a lot of respect for the newer engines.

On the other hand I am not ready for the big brother systems on the newer models. This is what is really dissuading me from buying a newer model. My wife fell in love with the GLC but we realized it was better to spend a couple thousand to fix up the ML and keep driving it especially since it's almost paid off.

As a point of interest, Land Rover used a shared design in it's Diesel and gas motors from the 1950's through the 1970's.