Hello all. New to the forum looking for some help.

This week I discovered a large leak in the driveway and haven't been able to figure out where exactly it's is coming from. What I have been able to determine is that it is diesel that's leaking, and I have a video showing the highest dripping point that I can find. The dripping seems to be coming from what I have determined to be the intake charge pipe muffler (?).... but I can't figure out why diesel would be dripping from this spot, or if it's coming from somewhere else and the drip is only showing up here. I would really appreciate any and all help with figuring this out, and advice on how to go about fixing it.

Two weekends ago I fixed a transmission leak (conductor plate replacement to fix the notorious electrical connector leak which a previous shop broke/stripped AND never replaced, but still charged me money for), so needless to say when I found out I now have another leak I got pretty tilted. It's all the more annoying that I have no idea where it's coming from.

The video showing the leak can be found here:

Thank you all in advance for the help/advice.
V

 

Good luck. I have had several leaks on my ‘05 CDI over its 230,000 miles and I’ll tell you what I recall.

1. Since the diesel fuel is so dirty, the fuel filter needs to be changed quite regularly. After 200,000 miles, mine started weeping stinky diesel fuel at a hose clamp and my wife complained of the smell. I replaced the fuel lines and special MB hose clamps up on top of the intake manifold. I used MB fuel lines since they have several bends and some have different diameters on each end. The spring loaded clamps take a special tool. I’ve heard that a small screw type hose clamp is fine but I just hate to second guess the MB engineers.
2. I also got the leaks around the fuel injectors and needed to replace the copper seals on top of the heads. These also stank badly. The engine cover comes off and then the foam sound absorption thing between the two cam covers. What I found was a black goo down in the cam valley. The fix was to pull the injectors out, (as I recall, disconnect the fuel fittings and hoses, then the long bolt that holds the clamp thing down, and finally pry out the injectors). Then carefully clean out the black gooey dried diesel fuel slime. I then purchased a counterbore tool to clean the sealing surface but am not sure it did anything. The copper seals are very inexpensive (maybe one dollar) but there is a white paste from MB with an innocuous name like “special sealing paste” used somewhere, (maybe on the copper seals or the threads). The paste is more expensive for the little bit you get. After all this work, I also replaced the long bolts and clamps.

It’s been a while, but I might have had to do the leaky injectors twice (maybe replacing the clamps the second time in there).

Good Luck,
Peter

 

BTW, while cleaning the black goo, I stuck a paper towel down the injector hole to reduce debris into the hole and cylinder.

I also used a “lady slipper” tool to pry the stuck injectors out. They are held in by the clamp and should just lift out but with all of the black goo, they are often stuck.

It has been a while, so I may have also warmed up the engine to soften the black goo as where the copper seals are cheap, the injectors are expensive.

I think,
Peter

 

I should also mention that the car just passed 80k miles and around the injectors everything looks relatively clean. The lines going to/from the fuel filter are also clean, no cracking, etc. I'm at a loss for what it could be.

 

Pull the engine cover. I think your fuel filter is located just above there with a couple of hoses going to it.

WK482

 

Do you think it's leaking where the fuel hoses connect on the other end (in red)? It doesn't appear to be leaking from the fuel filter side at all. It's completely clean with the exception of normal grime build-up over the years. I haven't traced them to see where they attach on the engine side.

 

The wonderful thing is that the leaks tend to be focused on one spot and not everywhere. I’ve put paper towels around things I think are leaking and any leaks are usually very easily isolated. I did have an oil leak that leaked from WAY above where I thought it would be but I eventually found the source (a bolt into an oil gallery).

Peter

 

Defiantly check out the hoses that supply the high pressure pump and fuel filter. At 203,000, one of these got so brittle on my 2005 CDI that I could break it with my hands. I bought some of the parts from a local dealer. They said it's very common to have this type of failure in older high mileage diesels.

 

Yeah, I'd be looking very closely at those hoses.