OM647 intake manifold install in an OM612

brianzero

2003 Freightliner OM612
So just my anecdotal experience with this swap, I didn't use that support bracket and I've been running now for 4000+ miles. I planned on getting that bracket from a junkyard when one pops up, I'm just here to say it isn't critical in the short term. Im sure many of you have thought about this too.
 

bcman

Active member
Question for the experts: How clean do the mating surfaces of the head and the manifold have to be? Below was what I started with today, after a quick wipe down:
1677204967378.png
I then spent a significant amount of time using brake cleaner and a red 3M Scotch Brite pad trying to sand the gunk off. I'm especially concerned with the carbon buildup around the exhaust port on the far right, which has some thickness to it. I think if I kept going, though, I'd just start wearing down aluminum. Here's what it looked like when I was finished:
1677205222421.png
Is this good enough for a new manifold gasket to properly seal? Or should i keep scrubbing? Is there another chemical, like oven cleaner, that would work better?
 

brianzero

2003 Freightliner OM612
That looks like youre almost there. One area of attention would be the far right bottom most hole which is the coolant passage. Try to clean that area best to get the gasket to seal there. I would use a flat razor blade, very carefully to scrape off any raised up deposits. A new razor blade, 90 degrees to the surface of the head, as you pull towards yourself will reveal any left over deposits. Im also a fan of easyoff.
 

brianzero

2003 Freightliner OM612
That looks like youre almost there. One area of attention would be the far right bottom most hole which is the coolant passage. Try to clean that area best to get the gasket to seal there. I would use a flat razor blade, very carefully to scrape off any raised up deposits. A new razor blade, 90 degrees to the surface of the head, as you pull towards yourself will reveal any left over deposits. Im also a fan of easyoff.
Also, you could use 400 sandpaper on a really flat block, and wetsand in a circular pattern.
 

bcman

Active member
OK, I finally completed the OM647 Intake Manifold swap. My van was out of commission for a bit over two weeks, but I had a nasty cold during that time, and several rainy days with no garage/carport to work under, and I also replaced glow plugs & module, Espar, electric coolant pump, and tried to track down an oil leak. For those attempting the swap, I would block out two full days to do it.

Here's all the parts needed to do it the way I did:
  • OM647 Intake Manifold
  • Manifold Support Bracket (MB part 647 096 00 45) (Note: this is Mopar part 05137201AA in the cross reference, but it's listed as a turbocharger bracket in the Mopar parts catalog. Best to buy it with the manifold, in person. It's a large triangular steel bracket.)
  • OM647 EGR Valve (MB part 646 142 01 19)
  • Intake Manifold Gasket (MB part 612 141 01 80) (Mopar part 05080324AA)
  • 4 of Intake Manifold Bolt (MB part 002 990 99 22) (Mopar part 05125741AA) M7x100 (?) screw
  • Coolant Hose for EGR (MB part 901 832 80 23) (Mopar part 05124887AA)
  • 3 of M6x40 screws to attach EGR to manifold (Note: Mopar parts catalog lists 06104008AA as M6x30 which is NOT LONG ENOUGH. But this may be a typo. MB part is N 910143 006004. I ordered M6x40 Stainless flange head screws from McMaster. It's stainless threading into aluminum, so I coated them with nickel anti-seize.)
  • 2 of M8x16 screws for new manifold support bracket. The OM612 Mani's support bracket is held with 3 M8 screws, each a different length. Only the shortest screw can be reused with the 647's bracket, to attach to the block. The upper screws need to be either cut down or replaced (or better yet, get them with the manifold and support bracket).
  • assorted other hardware: I used a 3/4" rubber-coated P-clamp to secure the wiring harness to the left side of the manifold, along with an M6 bolt & nut. I used an M6x40 screw with a 20mm standoff to attach the fuel pressure sensor to the manifold support bracket. I put a short section of 3/4" heat shrink tubing on the fuel return hose where it passes through the manifold. And about 40 zip-ties to reattach the plastic cover for the wiring harness and a few other odds & ends.
Pics and description coming soon...
 

bcman

Active member
Here's a few of the tools I used in this job:
  • E-torx sockets: Almost every screw head on this engine uses an external torx shape, mostly E10 and E12. Home Depot sells a 13-peice E-torx socket set that spans E-4 to E-24, and that's what I bought when I got the van. But the E10 and E12 are 3/8" drive, and thus are a bit bulky to get into the tight spaces needed to remove the bolts that hold the manifold to the head. You can use an 8mm 6-point socket for E-10 screws, but it's not ideal. If I were doing it again, I'd get a 1/4" drive E-10 socket.
  • 11mm 1/4" drive socket: There are 12 fasteners that hold the mani to the head, 10 are M7 screws with E10 heads, and two are double-threaded M7 studs with hex nuts. Those need an 11mm socket. When you remove those nuts, don't lose them! You're gonna have a hard time finding M7x1.00 hex nuts at your local hardware store.
  • Ratcheting 8mm combination wrench: This was especially helpful for getting the bottom rearmost screw off the manifold. It probably would have worked well on the other bottom screws, too. Mine was from a 5-piece set from HD. The 12-point splined shape does a good job of gripping the E-torx head.
  • 3/8" drive socket U-joint, 3" extensions: 3 or 4 of the lower screws on the OM612 mani are somewhat concealed by fins that join the intake runners. So you have to come at them from like a 30° angle. That's where the U-joint for your 3/8" ratchet comes in handy. I used the E10 socket, then the U-joint, then two 3" extensions, then the ratchet handle. (in hindsight, those screws might have been accessible by the 8mm ratcheting combo wrench.)
  • 1/4" wobble extension set: picked up this set after removal of the OM612 mani, and it made installation of the OM647 mani much easier. I was constantly switching between the 2", 4", and 6" extensions and my 8mm and 11mm sockets, and my 1/4" ratchet handle and 1/4" torque wrench. I think I might have used every combination thereof...
  • 7mm and 8mm sockets for the hose clamps on the intake, coolant, and fuel hoses. I used a mix of ratchet handle and 12V cordless impact driver to get these loose.
  • flush cutters: - to remove the zip-ties holding the wiring harness to the black plastic cover thingy, and for cutting the tails of the replacement zip-ties. I think I counted 35 zip-ties attached to that damn thing. Flush cutters allow you to clip the tails flush with the heads, so there's not a sharp end that will cut open your skin. Pro tip: nail clippers can also cut pretty flush, but you won't have the access for those when reinstalling. Buy the flush cutters.
  • right angle attachment for drill: attach one of these to your cordless impact driver, and you've got the fastest way to remove and install the 8 screws on the engine cover.
  • 14mm crow's foot wrench: The flare nut fittings on the hard lines that connect the fuel rail to the injectors can't be loosened with a traditional socket, but there's almost no access for an open wrench. I bought a set of crow's foot wrenches on Amazon, but only used the 14mm. I picked that set because the hex shape is angled with respect to the 3/8" drive socket, so you can flip it over to gain additional angle options.
  • 3/8" ID vinyl tubing: connect this to the drain cock on the radiator, and you can direct the coolant to a bucket instead of spilling it all over your frame and bumper. (I still got coolant everywhere when I disconnected the heater hoses)
 
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bcman

Active member
Steps for removal of old OM612 Manifold
  1. Start with the easy/obvious/straightforward stuff: Disconnect the battery. Remove the charge air hose that goes into the EGR valve. Remove the plastic engine cover. Disconnect the vacuum tube at the vacuum pump (use a flat screwdriver to push the red plastic collar away from the pump, then slide the tube off the pump).
  2. Disconnect the electrical connector on the EGR valve, and label it! I labeled all electrical connectors that I disconnected, because they're all going to have to go through the manifold at the end. I used blue painter's tape with a Sharpie. Remove the EGR. I believe it's 4 screws with E-10 heads on the manifold, and one screw with E-10 head on the stamped steel bracket connected to the engine hoist bracket.1678305702162.png
  3. Remove the 5 spring clips from the tops of the fuel injectors, and gently pry out the fuel return line connectors. I'd suggest covering the tops of the injectors with aluminum foil to keep dirt out.
  4. Drain coolant out of the radiator. Let the engine cool first! Find the red plastic knob on the back side of the radiator, near the bottom left (driver's side) corner. The drain cock is out of the left side at this location. Attach a 3/8" ID tube to the cock, and run it to a pan/bucket. It's probably easiest if you remove the grill and left headlight first to get better access. Open the valve. The red plastic knob may be black with grime, and hard to turn. Pliers around the outside, or a large flat screwdriver in the end, may help to loosen it. Be gentle; it's all plastic. 1678302743685.png
  5. Drain coolant from the engine/heater. Supposedly there's a drain cock on the engine block, just aft of the coolant hose from the oil cooler. I wasn't sure if this was it: 1678303135477.png so, I just disconnected the hoses at the Espar, since I was replacing that anyway. That got messy, though - it's hard to get a pan or bucket under those hoses. You just have to open a point on the heater circuit that's lower than the coolant passage in the cylinder head that feeds through the intake manifold. The inlet to the electric coolant pump might work, too, especially if you can point the hose downward after disconnecting from the pump.
  6. Remove the hoses from the water pump/thermostat that run to the radiator and expansion tank.
  7. Remove/disconnect the following fuel lines. I used rubber stoppers that came with my Mityvac kit to plug holes to keep out dirt.
    • All 5 hard lines connecting the injectors to the fuel rail. Use a 14mm open wrench, or 14mm crow's foot socket. Cover openings in foil.
    • The Voss connector at the top of the low pressure fuel pump (aka transfer pump). Push the arch of the white C clip toward the center of the connector, and gently pry the connector loose.
    • The clear plastic line connecting the fuel filter to the low pressure fuel pump. Both ends are Voss connectors and may break when you try to disconnect if they're old, and if you've ever had problems priming the pump after a filter change, it's a good idea anyway to replace this fuel line. You'll get new plastic tubing that you can see air bubbles through, new o-rings that won't leak, and unbroken connectors that will lock in place. Plus, you can scavenge one of the Voss connectors to make a pump priming tool with a Mityvac.
    • The Voss connector at the fuel pressure sensor that's teed off the line between low pressure pump and high pressure (aka injection) fuel pump.
    • The Voss connector at the fuel control valve at the back end of the fuel rail. This line runs from the high pressure pump, and yes, this connector is hard to get to, so save it for last so you get a feel for working on the other Voss connectors.
    • Disconnect the fuel return line at the fuel connector (the side coming from the engine. This is a black rubber hose that's clamped to the black plastic tee fitting on top of the filter with a hose clamp.
  8. Start disconnecting (and labeling!) electrical connectors on the top of the engine. Everything that runs under the black plastic wiring harness tray has to get disconnected, and freed from that tray. Some of these might not be accessible until you've removed/disconnected a nearby fuel line or coolant hose. All the connectors have some sort of catch mechanism molded into the plastic housing, on the long or short side, that must be pushed or pried open before removing the connector. It helps to gently push the connector in while releasing this catch, then pull the connector free. I'm working from memory, but here's all the connectors I remember:
    • EGR
    • (5) Fuel injectors
    • (5) Glow Plugs
    • Sensor in PCV vent tube (tube connects oil separator at cylinder head to intake just before turbo)
    • High Pressure Fuel Pump (AKA injection pump)
    • Fuel rail sensor, at front end of rail
    • Fuel control valve, at back end of rail
    • Coolant temp sensor, at water pump/thermostat
    • Camshaft position sensor, on cylinder head, passenger's side, near back
    • Low pressure fuel sensor, bolted to underside of intake manifold near front (and connected by a clear plastic fuel line to the low pressure pump)
    • fuel return line (temperature?) sensor, on a bracket between the cylinder head and fuel rail, near the middle of the rail. This one may be really hard to disconnect, so you can save it until the manifold is unbolted, but don't forget it!
  9. With all the connectors loose, you can unbolt the black plastic wiring harness tray. There's one E-10 screw on the cylinder head, and one on the left side of the intake manifold. You can also cut all the zip ties through the top with a knife or small set of flush cutters. I think I counted 25 zip-ties, but there may be more. If you want to avoid breaking it, you'll have to wait until the manifold is unbolted from the head, but don't worry too much about breaking it; you're going to have to cut off everything to the left (driver's side) of the fuel rail, maybe more.
 

bcman

Active member
Okay, getting close to removal time. OM612 mani removal steps, continued:
  1. If you haven't done it yet, disconnect the coolant hose that's the inlet to the electric coolant pump. Disconnect the other end from the black plastic hose that's bolted under the manifold, and remove this rubber hose.
  2. Remove the black stamped steel bracket that supports the intake manifold. There are two screws with E-12 heads on the underside of the manifold, which also mount the aforementioned black plastic coolant hose, and there's one more E-12 screw in the engine block down low. You may need to remove the fuel filter for better access.
  3. disconnect the other rubber coolant hose connected to that black plastic hose from its connection at the back end of the manifold. I don't have any pics from this in situ, but I mocked it up after removal:1678308050569.png Hose clamps removed, and I didn't get the relationship of the mani support bracket and the black plastic hose right (the steel bracket goes between the mani and the plastic hose). I loosened the hose clamp from underneath, lying under the transmission on the driver's side, and then gently pried the rubber hose off the nipple on the manifold using a flat screwdriver. Both the hose and manifold are going away, so don't worry about cutting or scratching either.
  4. There are 2 E-10 screws connecting the intake manifold to an aluminum bracket up top, near the back of the engine. Remove those.
  5. Time to remove the screws & nuts that hold the manifold to the head. There are 12 fasteners in total: ten M7 screws with E-10 heads, and two M7 studs with 11mm hex nuts. Depending on the access, you'll need combination wrenches, ratcheting wrenches, or sockets with varying extensions to reach all of them. I used my replacement OM647 manifold as a guide to get a better sense of where they all are, and also to keep track of how many I had removed and which ones remained. When I removed a screw, I put it in the corresponding hole of the new mani. 1678312368499.png The two studs on mine were in the locations shown above. They may be different on yours, or they may be all screws. I'm not sure if the location matters, but I can say it's much easier to mount a new manifold on studs than it is to line up screw holes while supporting a manifold with no studs. Apparently the engine guys at MB knew this, but didn't share with the wheel/hub guys. I needed to go underneath again for the lower screw farthest back, but I think all the others I could access from up top in front of the van. Maybe save yourself some time and get the coolant hose off the back and bring your 8mm ratcheting box wrench for this screw while you're underneath. For the middle 4 on the bottom row, I used a 3/8" socket u-joint adapter to get the correct angle of approach, since there are ribs/fins that connect the intake runners right where you'd want your extension to be. In hindsight, these might have also been accessible from underneath with a ratcheting box wrench, since the ribs don't go all the way to the flange.1678311891829.png
  6. With all 12 fasteners to the head removed, the manifold should be ready to remove. Mine was a bit sticky on one of the double-threaded studs, so I re-fastened the nut on the other stud, and gave it some steady rocking back and forth to free it (and Kroil overnight). Be careful not to bend the studs. Once it's free, start feeding your electrical connectors out through the gap between runners. Be careful not to pull too hard on any wires, and don't forget that fuel sensor connection if you didn't get it before!1678312824910.png1678312873584.png
Congratulate yourself on being halfway done.

Installation pics and description coming soon...
 

bcman

Active member
Installation of the OM647 Intake manifold is, in many ways, the easy part. The difference in size and access is night and day.
1681253361067.png
1. Before you begin, do your darnedest to clean off the mating surfaces on the new intake and the head. I did a lot of scrubbing with brake cleaner and a Scotch Brite pad. I started with this:
1681253849029.png
and ended with this:
1681253899501.png
I was most concerned with the caked-on black soot on the exhaust port, in the lower right corner. I tried easy-off oven cleaner at one point, but all it seemed to do was etch the clean aluminum. Some have suggested you could scrape it away with a razor blade, but I just scrubbed until the thickness was barely noticeable.
2. Reinstall your double-threaded M7 studs, and mount the gasket, and then test-fit your new manifold. The first thing you'll have to work on to prepare to reconnect everything is the routing for the fuel return line that goes to the filter. This rubber hose is crimp-fitted to the bracket with the fuel (temp?) sensor that's bolted between head and fuel rail, and it's not long enough to reach around the left (driver's) side of the mani to get to the filter. The way I see it, there are 3 ways to deal with this:
A. Break the crimp clamp and attach a longer piece of rubber fuel hose to the bracket with a hose clamp
B. Run the hose to a metal fuel line, part 647 070 00 32, that bolts to the OM647 intake:
1681254770118.png
Then, attach another length of rubber fuel hose from the bottom of that line to the filter with hose clamps.
C. Slip the hose down in the small hole in the intake manifold between cylinders 2 and 3.
I went with option C. I didn't have any extra fuel hose on hand, and didn't want to mess with the crimp clamp. I was concerned about abrasion of the hose going through that small hole, so I did a couple things to mitigate it: first, I slipped on some heat shrink tubing around the hose in the region where there would be contact. (Braided nylon loom would probably be even better.) Second, I got out the dremel and ground off the sharp edge in the middle of the hole where the two halves of the casting mold met. This made a nice smooth surface for the hose to pass through.
1681255197531.png
 

bcman

Active member
Home stretch now...
  1. You'll have to trim away just a little bit of plastic on the electrical connector for that return fuel line sensor (the same one that has the rubber hose that needs to connect to the fuel filter). 1681660587565.png It won't affect the structural integrity of the connector, but you will need to connect the connector before tightening the mounting bolts for the manifold. 1681660606022.png If you ever have to replace that sensor, you'll be unbolting it from the fuel rail anyway, so it shouldn't be a problem.
  2. Start installing your manifold bolts. Torque is 16 Nm (142 in-lb). Start with the middle ones and work your way to the ends. Even better, torque all of them to a lower value, then do a second pass at the full torque. Much like I did when removing the bolts & nuts, use the old manifold as a visual guide to help you keep track of which ones you've installed/torqued. I used bits of blue tape to make notes. 1681660823822.png
  3. With the mani bolted up, next step is to work on the wiring. Hopefully you labeled everything, but even if you didn't, the wires should have a bit of memory and tend to fall into place near the correct electrical connection. lay everything out near where it goes, but don't connect anything yet - you'll just have to disconnect most of them when you reattach the plastic wiring tray. I clipped mine just past the attachment to the fuel rail, and pre-threaded all of the zip ties: 1681660703521.png Start at the fuel rail, and methodically move the bundle of wires under the tray andclose each zip tie. Don't tighten until you've closed each one - you may screw up a couple, and you can sometimes cut a zip-tie open and reuse it if it's not tight. I had to re-do a couple of mine. When you've got everything attached to the tray you can snug up each tie, plug in each connector, and lay the tray down into the valve cover. There's one screw at the front of the engine that holds it in place, that's also shared with a ring connector in the harness (must be a ground wire).
  4. Attach the new manifold support bracket. This is the big triangular steel bracket that you hopefully procured with your mani. There are 3 M8 bolts with E-12 heads that held the old support bracket on, and the new one can re-use the shortest one that attaches to the block. Either cut down the long ones, or replace with 16mm long bolts.
  5. At this point, it's mostly a matter of reattaching stock stuff where it belongs: the fuel filter (if you removed it), fuel lines, radiator hoses, brake booster vacuum line, etc. The charge air hose coming up from the intercooler should click right in to the new manifold (you may have to harvest the little spring clip from your old OM612 EGR for the new OM647 manifold). One little bit of weirdness remains: Attaching the low pressure fuel sensor that tees off from the line between low and high pressure fuel pumps. It used to be bolted to the underside of the old mani. Some have just zip-tied this in place with the other plastic fuel lines, but there's a 6mm threaded hole in the new support bracket that's in just about the right place. I used a 20mm standoff that I had lying around , and a M6x40mm bolt to attach the sensor. I flipped the sensor around so the bolt goes through the hole in the opposite direction of the way it was before. You could probably just stack up 20mm worth of washers, or use a short bolt and just kinda stretch the plastic fuel hose a bit. You may also have to slip the plastic protective loom along the fuel line to protect any contact points with the new manifold. 1681662667426.png
 

bcman

Active member
The finishing touch is securing/protecting the wiring bundle as it wraps over the left side of the manifold. I chose to use a rubber-coarted 3/4" P-clamp attached to the tab on the left side with an M6 bolt & nut, but there may be other ways to do it.
1681745821623.png
After that, it's just a matter of refilling your coolant (make sure the drain cocks are closed!), prime your low pressure fuel pump, and get crankin! Don't be concerned if it takes many seconds of cranking, your fuel system has to refill all those hard lines between the rail and injectors. I would also recommend unplugging your electric coolant pump until you get it up to temperature, since you've let air into the heater loop, and the thermostat needs to open for the heater loop to refilll from the coolant reservoir. It's probably not great for the electric pump to run dry. Good luck!
 

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