350 CDI Charge pipe/ resonator leak

[Mike - CLS 350CDI]

New to this but want to share a leak I have had an issue with.
I serviced my 2012 CLS 350CDI including a fuel filter replacement. This wasn't as simple as it should be as the aluminium air charge pipe coming from the turbo towards the resonator was in the way of the fuel filter. Mercedes seem to have deliberately redesigned the charge pipe so it has two small "T" junction short pipes, one of them covering the filter. Have they done this deliberately or am I missing something? To get the charge pipe out the way so I could replace the filter I had to remove the resonator from the other end of the charge pipe (bolted to the engine by two small bolts) then manoeuvre the pipe off the turbo and block. When reassembling I realised the o ring seal between the charge pipe and resonator had split, I tried to source the o ring but after delivery of what I thought was the replacement from eBay was clearly the wrong size I decided to utilise an unused o ring seal I had that seemed to fit fine, one thing I wasn't sure of was where does the seal go? around the resonator pipe between the metal topper and the pipe lip? Or does it sit on top of the metal topper? I have tried the seal both ways, but still the leak persists. Does anyone know the correct configuration and have a link to the correct o ring seal? Has anyone else experienced an oil leak from the same place? It's not an oil leak as much rather a oil spray leak from when the turbo system is pressurised. It's not leaking from the car but I am conscious it's spraying oil around the front of the engine and into the pulleys and serpentine belt.

 

[Druk]

I've had the same bother exactly. My leak was from the rear seal and sprays oil but doesn't seem to affect performance. After all the trouble wangling the pipe out I cut it at the front about four inches up and that way the two halves are easily manoeuvred into place. Once there they are joined by a short length of silicon turbo pipe and a couple of clips. Next time the filter needs changed its a matter of releasing the rear section. Seemples.
IIRC it's a pale green silicon rubber O ring that goes over the pipe end at the rear joint. This pushes into the turbo female end easily if the pipe is cut as above but doesn't if it's not.

Welcome to the forum BTW

 

[Mike - CLS 350CDI]

Thanks Druk.
Did you manage to stop the leak?
Its a poor design the way the charge pipe and resonator are connected. The seal relys on the two being perfectly positioned to ensure that seal sits right. Whereas the pipe on the other end going to the intercooler has a proper clip making a better deal.
I was thinking to just put a straight through turbo pipe to from he charge pipe to the intercooler. Anyone done this and has it caused any issues? I know if I do I have to be careful the pipe doesn't flex near the serpentine belt.

 

[Druk]

I get a real bee in my bonnet when confronted by stupid thoughtless engineering and always try to do something about it. I wouldn't be posting about this if it hadn't been a complete success. Having said that i wouldn't go replacing the whole pipe length as I believe the two nodes welded to the pipe sides have something to do with the resonance and removing them may have a detrimental effect. By cutting the pipe the O-ring seals get a chance to self align and are much, much easier to replace. The long section is held perfectly well by the central screw and the short rubber joiner anchors the bottom short length perfectly. Poor pic here taken with my phone but shows the joiner section hard up against the lower clip. iirc I cut maybe 1/2" out of the total length to allow for manoeuvring the rubber in.

 

[Mike - CLS 350CDI]

Looks spot on, thanks I will give it a go.

 

[Druk]

Another pic showing protective sponge rubber held by two tie-wraps to prevent the rad hose chaffing on the Jubilee clips.

 

[Mike - CLS 350CDI]

Yes looks a good job. Thanks for the pics.
I have put it back together now and will take a look some time through the week to check if the cleaned area shows any sign of the leak returning.

I managed to manoeuvre the resonator and fix it in place so the pipe bolt when positioned showed a small gap underneath, so hopefully when tightened it formed a better seat and seal for the pipe and resonator. Time will tell but worse case I can use the fix you have shown, thanks.

I'm going to post another re the front lights. It's an AMG with the turning lights (sorry not technical term) but I was reversed into and long story short after fixing the damage I am now left with no turning lights and a right indicator that thinks a bulb is gone but actually they work fine from outside.

Anyway if you can help let me know.

 

[GregCa]

DRUK - Your Silicon pipe solution is excellent. Yesterday I spent 2 hours trying to get the aluminium pipe off. I gave up, something I do normally do. I could not locate the bolts on the front box. Can you point me to more information on Silicon tubing (internal diameter, supplier?). I do not intend to do anything until I have the tube ready. Has anyone else gone down this route? I also agree it seems as if everything on this car has been made as awkward as possible to get at. I have worked on cars for 45 years and this seems one of the worst. I am a new member to this forum and I cannot find how to mail a member directly is this possible?

 

[MrGreedy]

Try this very recent thread

OM642 Green O-Ring replacement instructions?

I've put instructions on removal and listed all the charge line seals for the 265bhp engine.
For buying, call MB Grangemouth. Each seal is less than you will find on eBay and via Reg search by the dealer, will be exactly the correct one. £5 postage per package, or free collection if you have a local Arnold Clark

 

[GregCa]

MrGreedy or Druk - The info on the Green O ring replacement is useful - i may shortly have some good news on obtaining suitable replacements.
I suspect that they get snapped with all the wiggling that goes on whilst wrestling the charge pipe off the turbo. Mine was fine until I did this.....
I think that the Silicone add in tube is the way to go due to the ease of getting off next time the fuel filter needs replacing. Druk if you are out there I ask why you picked the part of the pipe you did? I am planning on a few centimetres after the turbo coupling over the fuel filter. this looks more accessible and on the horizontal instead of the bend at the front next to Resonator. Has anyone else modified the charge pipe?

 

[MrGreedy]

I'll probably do this as well, so I'd be interested in the outcome.

What internal diameter of silicone pipe is required please?

 

[GregCa]

I'll probably do this as well, so I'd be interested in the outcome.

What internal diameter of silicone pipe is required please?

I have ordered Black straight silicone tube 3" long with 51mm (2") ID wall thickness 5mm so 61mm OD and 2 high quality clamps
T-Bolt W2 Stainless Steel Hose Clamps to fit 59-63mm dia pipe. Both items from Ebay. Delivery expected in over a week due to Covid 19.
I cannot get the charge pie fully off the car due to the cable tray which I do not want to remove. So I will put protection under the pipe before I cut it to stop the debris going everywhere. i will measure thrice and cut twice to remove about 2 cm and then hopefully all will go back together better than before. I will post photos when the job is done. Worst case I will have to buy a replacement charge pipe which I see are available second hand in the www.

 

[MrGreedy]

I don't know what sizes silicone pipe comes in and how it fits on to rigid pipes. The aluminium charge pipe is 49.90mm external diameter on my car; just measured it and boy, there is not a lot of room to spare on the top of the engine with all the gubbins!

 

[GregCa]

Are you sure about the size? Did you measure with calipers? I checked mine several times.
This link should be useful as these are all the silicone tubing ID's available. They appear to change by 1/8" or 3mm.
So your 50mm would be a squeeze for the 48mm ID tubing. I do not think my charge pipe would go into this size so I have gone for the 51mm and hope the clamp will tighten it. I may have to resort to some silicone tape around the tube if it is loose.

 

[GregCa]

Sorry forgot this link www.advancedfluidsolutions.co.uk/51mm-2-id-blue-silicone-hose-784-p.asp

 

[MrGreedy]

Are you sure about the size? Did you measure with calipers?

Yes, I've got some digital vernier calipers, accurate to 0.01mm.

Having had a look at silicone tubing, they say don't put something on too small that stretches, otherwise the internal surface of the tube can break up and of course go into the turbo. I'm going to use 51mm ID tubing as well.

 

[GregCa]

If necessary I will use a couple of turns around the air tube of PTFE tape (gas grade a bit thicker) - temperature range -260 to +260 C and is not effected by oil, diesel etc.