Ok... here goes the giant post.
What I set out to do was an oil cooler reseal, putting everything back to stock. What I ended up doing was inventing a Sprinter manifold conversion for passenger car OM642s. There was an amount of scope creep involved.
In looking at the volume of material, I'm going to break this up into four groups totaling seven big posts: Disassembly to access the oil cooler, Oil cooler re-seal, The Sprinter manifold conversion, and fixing the handiwork of the baboon who worked on it before me.
1. Disassembly to Access the Oil Cooler
Across all applications, the OM642 *long block* is the same in a given year; I didn't even try to audit long block changes by year. All versions have an aluminum block and aluminum heads. There are two major families of applications that use different sets of parts added onto the basic long block: van and passenger car(*). The two have different intake manifolds, intake splitter necks, EGR systems, heater connections and low pressure fuel piping (and probably a bunch of other differences I didn't catch). The exhaust manifolds appear to be the same, although there were several different versions of the turbo Y-pipe that connects them to the turbine inlet.
(*)The Benz parts look up shows Passenger Car, Cross-country Vehicle, Van and Smart as the their four major product families. The Cross-Country Vehicle is the G-class. I do not know if the G-class config of the engine differs from either the passenger car or van configs or in what ways it may be different. I have not heard of the G-class config having specific parts so I conjecture that it uses the passenger car engine family.
The OM642 was introduced in 2007, and is STILL in production. It was used extensively across the Mercedes-Benz product line in E-class, S-class, R-class, G-class, GL-class, GLK-class, ML-class and probably more models that I'm missing. Its use in passenger cars has been superseded by newer engines, but it is still used in vans. Obviously the van versions have been used in Dodge, Freightliner and Mercedes-Benz Sprinters for 17 years. The engine is designed to spend its entire half-million kilometer service life pulling a 20,000# Sprinter based bus over the Austrian Alps. It's been offered from the factory with outputs as high as 261 HP and 457 ftlbs. In the WK it's about 215 HP and 376 ftlbs.
Since it has such a long production history with such a broad range of model applications, there are approximately 14,000,605 configurations listed in the Benz ISPPI After-Sales Platform.
The very first time I realized I needed to order a particular widget for this engine, I realized that I would need to look up what engine configuration I had. There is a 197 page diesel addendum to the 7199 page WK service manual. Seriously, the WK service manual is nearly 7200 pages and almost 150 megabytes as a .pdf. The diesel addendum in fact has a section on engine identification. The engine identification code is stamped into the forward face of the block just below the left cylinder head deck surface. That's below the overhanging high pressure pump and really F@#$%ing hard to see with the engine in the vehicle. The engine code includes the three digit model code (642...), the three digit configuration code, the one digit plant code and a seven digit serial number. Also stamped on the front of the block are a four digit code for the select-fit main bearings and a six digit code for the select fit piston sizes. No over-boring is permitted per the factory literature, so if you find a bore out of spec, replace the block. A truly German solution.
If you think that's difficult to read in this situation, you would be correct. My configuration code, and I suspect the same for all WKs, is 980. This is the example code shown in the manual addendum, including a callout noting "980 = WH". I think a WH is either a RHD WK or just a non-US WK.
The Benz ISPPI does *not* list a 980 configuration.
Of course not! Why would a Benz database list a configuration for a Benz engine? Even though it was used in a Jeep, they were the same company when it was built! This made me a little circumspect about ordering parts. Fortunately I didn't have to order many.
Getting into actually taking things apart... Here's how it started:
Because it had been leaking oil for thousands of miles and was covered in filth and grime, I cleaned it up a bit before I started. I just left it running while I sprayed it down with the low pressure setting on a wand-type car wash.
To say this engine is...
intricate... is in contention for the understatement of the century. Everything overlaps everything else. Efficient disassembly and reassembly is extremely dependent on order of operations. The diesel addendum does not cover these operations in sufficient detail. The factory assembly instructions must be extensive.
For me an important aspect of this operation was to remove the fewest possible components of the high pressure fuel system in order to reduce the number of fittings I'd have to protect from FOD while I had the system apart, which I was sure would be at least a few weeks. The system runs ~4500 psi of fuel pressure at idle and 23,000 psi at WOT; it's very sensitive to FOD. Leaving the fuel rails installed was slightly inconvenient for later operations, but not a big deal. Removing the high pressure crossover tube without completely removing the rails was awkward. I had to unbolt the rails from the valve covers and slightly flex the high pressure lines from the rails to the injectors in order to have enough clearance to remove the crossover. I also left the harness in place, partly because it would just have been much more inconvenient to remove; partly to give myself a chance at getting everything plugged back in right; partly because some of the connectors had been mis-routed by some baboon working on it before me, making the harness look more difficult to remove than it would have been.
Here are a couple of shots of initial disassembly:
This one was my fault. Keeping the o-ring between the compressor outlet and charge tube in place during assembly is apparently quite difficult. Oddly enough, this did not give me an underboost code. On eventual reassembly, I used the hook end of a cotter pin puller to poke the new o-ring back into place when it tried to do exactly the same thing.
Widgets and brackets and doodads, oh my!
In trying to take all the small stuff off first without taking big steps to take things apart, it quickly becomes apparent that you can not actually take very much off before you must remove the turbo to make any further progress. So I got started removing the turbo. I watched a couple of YouTube videos covering turbo removal with the engine in a W211 or W212 E-class. The firewall in that body is vertical behind the turbo, making access to the Y-pipe bolts not exactly easy, but feasible. In the WK body, the cowl/HVAC intake overhangs the turbo, making access much more difficult and much more fussy.
The turbo heat shield sits on the right on a bracket that also supports the transmission dipstick tube; on the left on the EGR valve. The heat shield is awkward to remove because the cowl is close and the shield needs to be sprung out of shape a little bit to come out.
There are three bolts/studs/nuts holding the turbine outlet elbow to the turbo (E12 or hex M8x1.25mm) and a V-band clamp with a 13mm nut securing the outlet elbow to the pre-cat. There are three bolts holding each manifold to the turbo Y-pipe (E12 head M8x1.25mm). There are two bolts at each end of the EGR tube holding it to the Y-pipe and left intake manifold (E10 head M6x1.0mm). There is a bracket bolted to the Y-pipe which has two vertical bolts attaching it to the bellhousing ring on the engine block (E12 head M8x1.25mm). And lastly, there are two bolts attaching the turbo to the turbo pedestal (T40 head M8x1.25mm shoulder bolts). Pressurized oil is delivered to the turbo through the turbo pedestal, and effluent oil also drains back through the pedestal. Pretty much every bolt requires a different combo of extensions to access it. One of the 8mm bolts between the right exhaust manifold and the Y-pipe had been replaced by an M6 through-bolt with a nut on the back. At disassembly, I assumed that some baboon in the vehicle's history had simply lost the correct bolt and replaced it with what they had. This assumption would come back to bite me later.
There is an electrical connection to the variable turbine nozzle actuator which obviously needs to be unplugged first as well.
But it finally comes out
Note that in this photo, the previous baboon had left out the bolts attaching the bracket to the Y-pipe. This was dumb, as the easier removal is via the bolts holding the bracket to the block. The bracket should come out with the Y-pipe.
One of the E10 head M6 bolts holding the EGR tube flange to the Y-pipe rounded off in situ. I used a chisel to cut the EGR pipe off at the flange. Once I had the Y-pipe out, I was able to rotate the flange to loosen the bolt.
I did a few steps before I took another photo, but those steps are straightforward disassembly. The OM642 has a cam driven vacuum pump on the right cylinder head, more or less mirroring the timing chain-driven high pressure fuel pump on the left cylinder head. In a WK, the vacuum pump must be removed in order to have space through which to remove the intake splitter neck. The alternative is blowing down the AC and removing the AC tubes from the engine bay... and then having the protect the AC system from FOD for the remainder of the job. There is a bracket on the exhaust side of the right cylinder head that supports the "normally-open" (NO) throttle at the end of the intake splitter neck. That bracket is somewhat fussy to access, but overall intake neck removal is not difficult.
The thermostat mechanism is integrated into the thermostat neck and is not a separate part. The thermostat neck can be unbolted at this point as well. Obvi that involves draining the coolant. That's easy, as there's a hand-operated drain petcock built into the factory radiator. The shape of the EGR cooler makes the entire cooler a local low spot in the cooling system, so it does *NOT* drain when the rest of the system does. A little coolant remained in the intakes as well, probably because the vehicle was tilted a little to the right as I was working on it.
The high pressure fuel crossover tube is still in place in this photo. To remove it, I loosened the fittings, unbolted the fuel rails from the cylinder heads, and gently pulled/pried everything apart until I could get one end of the crossover tube out. I think it is was the end angled down. I then bagged the crossover tube in a 1 gallon ziploc and wrapped the fuel rail fittings in saran wrap secured by rubber bands.
The OM642 flows coolant through the EGR cooler before it goes to the heater core; this routing probably helps it warm up more quickly on a cold start (in Finland...). The connection from the EGR portion of the left intake manifold to the heater core is at the back of the left cylinder head. There is also a smaller coolant connection between the EGR valve itself and the cylinder head that also needs to be disconnected. Electrical connections include the exhaust pressure sensor and the EGR valve itself.
Both intake manifolds, the swirl flap actuator and the EGR cooler all come out as a unit. Note that the intake manifolds have to come out to replace the swirl flap actuator. This design "feature" encourages swirl flap motor deletes when the swirl flap motor fails.
Unbolting the intake manifolds is fairly straightforward. Notice that there are 3-4 different lengths of manifold bolt. Also notice that the manifold bolts, including one from the thermostat, are M
7x1.0mm. Dammit, Karl. When I took mine apart, half the bolts were in the wrong holes for their lengths, thanks to previous baboon.
Slipping pieces of cardboard in between the intake manifolds and the cylinder heads helps minimize coolant dripping out of the manifolds and EGR cooler--and into the intake ports--as you remove the assembly. After what seems like an infinite number of doodads and widgets and an incredible amount of fussiness, the assembly comes out and you have this:
The prize is in sight!
I don't think I snagged a photo of only the assembly of the intake manifolds with the EGR cooler... but since they didn't go back into the car, I still can!
