S320 cdi Inlet manifold and egr removal

paulkno

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S-Class W220 2002 320CDI
Just found the solenoid and connector arm for the flaps on my inlet manifold had come disconnected. The EGR was clogged so I figure the rest of the related housing and inlet manifold will be too. I'm in the process of removing the whole lot but can't see whats holding the egr cooler in place. Its bolted at one end but the other end and centre pipe just look like push fit. Is that correct? Removed the bolts but it's pretty solid and I don't want to force it.
Anyone know how to remove the cooler properly?
 
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paulkno

New Member
Joined
Apr 3, 2017
Messages
7
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4
Location
Manchester
Your Mercedes
S-Class W220 2002 320CDI
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Update:

Just fyi its push fit.

So essentially I was solving the lack of power problem that many cdi owners talk of. The symptoms are the car is driving normally then when you demand more power the car just trundles along and hardly accelerates. It may rev up but your don't really go anywhere and have a serious lack of torque.
Many owners talk of EGR problems and limp mode. However in this case as with many there is no error msg or code stored to be read. ie this is not limp mode and the car is assuming that all sensory data is correct and is not flagging an error.

The EGR valve on this 320cdi engine is vacuum operated. I opened up the valve and of course it was fairly well clogged with soot. It is totally possible to clean and free up the EGR valve. Very easy to access on top of the inlet manifold and only three torx screws holding it together. It's worth noting that the valve is in the mixing chamber and not the removable vacuum operated actuator. Both will need cleaning and freeing up.

I figured if these were clogged then the inlet manifold is sure to be also. There is a solenoid on the bottom of the inlet manifold that operates flaps inside. You can check the operation of this by manually moving the solenoid and seeing if it moves freely. Chances are if your inlet is clogged then the flaps won't budge and/or the ball and socket joint on the solenoid has slipped off while it was trying to open the jammed flaps. A sure sign you have a clogged manifold. This one had done 140k miles and is a 2002.

I removed the entire manifold assy. I did this from above without ramps, however I wouldn't recommend it. Its a long fiddly job and the fuel rail and filter will need to be partially removed for access. Also there are 8 wires routed between the manifold pipes, so you'll have to unplug all these. One goes to the gearbox, another is an earth for the starter motor, another to the manifold pressure sensor and one to the (I'm gonna call it a water pump) I'm not sure exactly what it does, but it is mounted to the underside of the inlet manifold and brings water through the egr cooler. This will also have to be disconnected. Very tricky from above with spring clips holding the water pipes on. The EGR cooler also has to come off, don't drop the gasket at the exhaust end. Then at the front there are further wires to the oil level sender on the sump (has to be unplugged from underneath, you don't need ramps but the trays will have to come off. Although you've probably already removed these to collect all the screws and ratchets you've dropped). Now theres a wire to the solenoid, another to what I think is a unit to do with the brakes or water system. And a finally a wire to the sensor on the air pipe from the turbo side.

Once you've removed all the torx nuts holding the manifold on you can remove it and you'll probably find its almost totally clogged. Out all the inlets this one only had about three weren't blocked and the flaps we're totally jammed.

I cleaned it all out and refitted. Now it pulls like a train.

Once refitted the engine will need repeated cranking as the fuel was disconnected and you probably lost some. Make sure you have a battery boost handy, eventually it will start. You'll also need to top up the coolant as you'll have lost some from that too from the weird water pump thingy mounted to the bottom of the inlet.

Unless you are fairly competent, have good tooling and are brave, I wouldn't recommend doing this job at home. If you have access to ramps or a pit, much easier.
 


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