97 E300D Crossover/Manifold/Flaps
 

Thanks to info from Jeremy and other owners of 96 and 97 E300D's, I am ready to take on a few jobs on my 209K mile car:

-Eliminate P0200 and associated P1975 codes that are popping up (resonance switchover valve not actuating)
-Clean crossover and intake manifold (they are dirty)
-Replace any hoses, o-rings, etc that may be a problem as long as I am in here

I removed the crossover and top cover, and took some pics to show what it looks like before. Do you see the oil (or is it fuel) that has filled up the rearmost well? The front-most ones look pretty clean by comparison. For those that have done this, what do I need to replace? Part numbers? The cleaning part I can handle, may even take to a place that can dip clean the manifold and crossover. For the rest of it I am looking for input.

Be very careful of the wires connecting to the switchover valves. I broke a wire and ended up taking it to dealer to located the break in wire. I would definately find a place to dip it, its a real messy job trying with diesel, brake cleaner etc. You are probably going to need the entire PCV system, those nipples get brittle and break when you try to remove them from the intake. Good luck, yours looks cleaner than mine when I removed it.

The liquid in the injector well is condensed oil from the PCV system. Mine has it too...

Do yourself a favor and buy some new injector line clips and shims. I believe I can see rust on one line where it's been vibrating against the mount because it's not clipped. I've never seen it happen but I can imagine that this will eventually fail depending on how long you own the car.

Part numbers are:

601 078 03 86 for the shims and

603 078 01 41 for the clips.

7 are required but you may want a couple more of the plastic clips incase of future breakage. They're really cheap.

Terry and I have been discussing this matter via email. It appears that the '97 has an electrical device on the (vacuum-actuated) flaps that 'tune' the intake pipes; the '96 lacks this "feature" ("curse?") so I have been unable to give Terry the support he needs. Terry's car is throwing codes (P1475) because something (the electrical device?) is not sending the proper signal to the IFI so it thinks the flap is not working correctly.

The plastic clips are 603 078 01 41, $4.05 in February 2008 and $3.44 after my 15% MBCA discount. YMMV. I have also heard of injector lines fracturing from vibration if they are not tied down.

The top of my valve cover was equally as bad as Terry's (see this thread). I ended up replacing a lot of the bits and pieces that direct the blowby into the 12 intakes.

Terry, please post a picture of the flap in the crossover pipe. I want to see this electrical thing you have mentioned.

Jeremy

The clips are available right here on the Fastlane parts system... :)

Terry, what is the manufacturing date on your car? I looked in the ETM, the electrical part of the factory DVD manual. The diagrams look the same for you '97 as my '96, I don't see anything that would tell the IFI that a flap is working or not. A picture of the flap in the crossover pipe of your '97 would be helpful. Mine (1996, built 10/95) has a vacuum line to the flap and that's all. The "switchover valve" has a pair of wires and vacuum in/out for each of two valves (built into one case).

Definitely take the manifold to a machine shop to be hot-tanked. Best $25 bucks you'll ever spend. That is a nasty nasty job if you try and DIY. I have some before & after photos of this in my 606 head removal thread, here: http://www.peachparts.com/shopforum/diesel-discussion/208998-606-head-removal.html

I think there's a sticky in the parts forum here that includes all the CCV pipe and elbow pieces. Yours will be brittle and break apart as you remove them from the intake manifold.

Thanks for all the responses. So it looks like recommendation is clean stuff up, replace shims and clips, and possibly all the hardened hoses that are part of the elaborate CCV system.

What about the injector lines, any need to replace lines or o-rings? I think all the crud build-up is from the CCV system, so hoping to not have to dig into the injector lines, but if it is easy and cheap, maybe a good time to do some more of this work. Let me know what you think.

On the flap, I am guessing the code is being thrown because the wiring that gives actuation feedback is a problem. I will inspect later tonight. I can see the flap actuating properly at 1500 rpm, just as expected, so the solenoids and vacuum lines are all doing their job. The other possibility is the valve is sticking and I just happened to catch it when it was working OK. But resetting code usually causes it to come back within a few miles, so it is a pretty consistent code throwing.

There is definitely an electrical connector and a vacuum line at the valve itself, I will snap a pic tonight and include it. I will also get manufacture date.

Cyl #6 looks like a leaky return line to me, mixed with some oil possibly.

The newer retrun line material is a very light gray color, those are black so must be at least a few years old.

What is best way to clean all the gunk of the top of that engine? I suppose a towel and some degreaser and a bunch of time is about the only way to do it.

Is it very hard to replace those return lines? Any part numbers for those?

Already scheduled a shop to dip the manifold and crossver at a price of $20. A bargain, as far as I am concerned. They will let it sit for the weekend and pick up on Monday.

The return lines can be purchased at a Mercedes dealer and some other auto shops will have standard 1/8 rubber hose. Make sure it is compatible with diesel fuel (not vacuum hose). You might also consider spending the extra money and get Viton hose from a place such as Fryerpower. That way, if you ever happen to use biodiesel, you won't have to worry about the lines being damaged.

Cleaning the top of the valve cover is just a slow, messy chore. Wear rubber gloves, use disposable rags or paper towels. Almost any solvent will work, anything from biodiesel to WD-40. Depending on the flammability and toxicity of the solvent, you might wish to do the work in the open air. (Another advantage of biodiesel is that it is minimally flammable/toxic.)

If you replace the return hoses and the CCV pipe forest (the hard plastic lines are usually OK; the rubber elbows and tees tend to harden with age) then you will have no more leaks and the valve cover will stay clean.

Jeremy

That was kind of fun, and dirty! Took off that manifold tonight, and there is probably a good eighth to quarter inch of black soot coating everything on the inside. I would estimate that a couple of the ports were 30% blocked. The front one was particularly bad.

Observations/Questions:
-If you do this, make sure to count 14 bolts on the manifold. I took 13 off and didn't see the one that is recesssed in a quite different location. Tugged on the manifold pretty good before I realized one more bolt needed to come off. Also, be careful on removing these torx head bolts. I was very careful to use the right size and apply good downward force while turning. Stripping one would be very bad! I used a 1/2" socket with a sturdy handle to get enough torque to turn these bolts as they were tight.

-Every single one of the CCV connectors that plug into the manifold broke off. They are as hard as a rock. Fishing the peices out of the manifold was a tedious task (see pic).

-The flaps do have electric switches which check to make sure they open all the way (see pic). I guess the '96 model doesn't have these.

-The A valve under the manifold is larger and was in good condition, other than being dirty. I think the B valve under the crossover was my culprit. Using my hand vac tool, it takes quite a bit of vacuum to get it to actuate, and sometimes it just will not open enough to trip that switch. Once I get her cleaned up, I hope this little flap will open with ease and eliminate that P1475 code.

-Can I use my intake gasket again? Looks OK if I clean it up. Or is it just smart to replace it. Anyone know cost?

-How do you replace those return hoses? Do you just pull them off? The way they go down into those wells, I just want to make sure I know what I am doing before I start tugging on them.

-I am concerned about an effective way to clean the intake part of the head. The passages go very deep down to the intake valves, I assume that I will not be able to do a very thorough cleaning on those. I also think some chunks of this sooty material have fallen down into these passages as I pulled the manifold off. I may just try to vacuum out any chunks I see.

I'll keep you posted as I move forward!!!

Terry, you are doing great! That is exactly what I had to do to my '96. Yes, the '97 has electrical things on the flaps that the '96 lacks, explains why you were getting codes. I probably missed 'em when I looked at the very complicated schematic. Yes, scrape as much carbon out of the intakes as you can while holding the hose of a vacuum cleaner up to the port. Tip: don't use your wife's vacuum cleaner, use the shop vac. Remember that the head is aluminum, use a hard plastic tool so you don't scrape into the metal.

You'll save a lot of money and learn something by doing this yourself; when the dealer sees this, they just replace everything except for the manifold and the crossover. Those flaps are over $100 apiece, as I recall, they did that to one of my POs. All they need is to be cleaned up of all the carbon. It will also give you an incentive to block off the EGR valve so the insides will stay clean once you are finished. You can clean and re-use the intake manifold gasket; I replaced mine, it was only $15. I also replaced the big o-rings in the crossover pipe and its connections; they were several dollars apiece. Putting a little grease on the o-rings will make the pipes slide together more easily. I use a silicone high-vacuum grease that I got years ago.

I recommend using anti-seize on those Torx bolts and on any steel bolt that goes into aluminum (such as glow plugs). Makes them a lot easier to remove the next time.

Be careful with the wires that go to the vacuum solenoid in your first picture; the insulation will be very brittle. Mine has already been repaired once and I need to completely rebuild it some day.

Hey Jeremy (or anyone), how about those fuel return lines? How do those come off? Do they just pull off?

Correct. They are pushed over a barbed nipple on the inj. Pulling on them after installing is how most leaks develop; especially as the line ages and becomes more brittle.

Put some masking tape over the intakes before you begin losing pieces of metal fuel line plsastic hold down clips down those holes......most of us have expirienced that already.