606 fuel leak - where is it coming from? - PeachParts Mercedes-Benz Forum

tankowner · #1 11-06-2009, 04:46 AM

Alright, so the '95 continues to leak fuel from the engine compartment. Pretty decent puddles that leak down from somewhere in the vicinity of the IP. I have taken the top down approach and have already had the intake manifold off to inspect and change out some o-rings. I have replaced all of the orings on all of the plastic fuel lines - but to no avail. I thought the leak was coming from one of two lines that connect to the lift pump, but that has not solved the problem. Interestingly enough, the substantial fuel leak does not affect driving - no hesitating, etc. - so does that help isolate where the leak is? Where should I go next? I haven't had to do much work on this car since I bought it, but now it is giving me a run for my money.

I have learned about the U-clips and that they should be pulled out when the fuel line connectors are installed (pushed in to remove) - mine were all pushed in. I had to buy a replacement line since I broke a connector on one of the lines - but now I am thinking I might just replace all of the lines anyway - that are relatively cheap.

Anyway - where do you guys think I should go next? Likely leak areas? SOV?

muleears · #2 11-06-2009, 06:38 AM

I vote for the O ring behind the SOV. Or is it possibly running down one of the lines from the secondary filter and making it look like the leak is around the IP?

matthias08 · #3 11-06-2009, 07:42 AM

i've had this problem for a few months now... just minus the puddles... but it was giving a very, um, bold odor inside the cabin...

found it was leaking around the IP, and seeping around a couple O rings...

wish you the best of luck!

Matt

tankowner · #4 11-06-2009, 10:15 AM

Quote:

Originally Posted by muleears

I vote for the O ring behind the SOV. Or is it possibly running down one of the lines from the secondary filter and making it look like the leak is around the IP?

That is my next best guess. It's not running down any of the lines from the filters. I have changed the orings on all and wiped the lines down - they remain clean.

Anybody know how many orings are at the SOV? Are the sizes the same as the ones on the fuel line connectors? I think Terry has this info in previous post - probably applies to the 606.910.

tankowner · #5 11-06-2009, 10:17 AM

Quote:

Originally Posted by matthias08

i've had this problem for a few months now... just minus the puddles... but it was giving a very, um, bold odor inside the cabin...

found it was leaking around the IP, and seeping around a couple O rings...

wish you the best of luck!

Matt

Thanks Matt. Do you recall which o-rings? I have replaced the orings on the two lines that go to and from the lift pump. How about the actual IP, should I suspect something there?

Diesel911 · #6 11-06-2009, 11:42 AM

See what you can find at the Russian EPC site:
for the IP
http://www.detali.ru/cat/oem_mb1.asp?TP=1&F=124131&M=606%2E910&GA=722%2E435&GM=717%2E433&CT=M&Cat=19T&SID=07

To the Vehicle look up section:
http://www.detali.ru/cat/oem_mb0.asp?TP=1

TMAllison · #7 11-06-2009, 02:46 PM

Other than the orings on the fuel line ends there is only one other oring sealing the SOV. It seals a nipple (inserts into the IP) behind the SOV.

The dot 910 size is the same as I posted previously for the dot 962 SOV oring.

Spraying the fuel lines and IP down with a can of brake cleaner ought to help you figure out where the leak is comming from. Should be easy to find if it is enough fuel to mark the garage floor.

GregMN · #8 11-06-2009, 03:13 PM

How I found a leak on my 606:
Clean and dry the area to be searched.
Remove the fuel source hose from the hard line. Be ready with a plug for the hard line from the tank.
Pressurize the fuel line, no more than about 5 psi. I used an electric fuel pump in that line that is set to 5psi.
Found the leak in less then one minute.

For your information, I have found that a person can pressurize a hose, up to about 8psi, by blowing on it. Patch a clean piece of hose in and blow. It might work.

Mine is an 96 drive by wire and the leak was between the fuel control unit and the IP. You don't have that part.

tankowner · #9 11-06-2009, 09:02 PM

Thanks for the good tips guys. I am going to have another crack at it tomorrow morning. I will let you know what I find.

NY300SD · #10 11-06-2009, 10:03 PM

tankowner, I'm looking forward to your diagnosis.

I have a similar problem. I seem to have a leak right right around # 62, (at the back of the IP) but it's hard to tell. The engine mount and the "SOLENOID" is damp, but the sound panel seems dry. I'll need to take the intake off to get a better look. Though I'm not sure when that will happen as this is my only vehicle.

tankowner · #11 11-07-2009, 05:33 PM

Alright, I have been tearing at this all day and have figured out where the leak is coming from. Unfortunately I have mucked up the SOV in the process, but I think I can fix that. Anyway, the fuel is coming out of the IP - between the body and one of those starburst shaped fittings (sorry, I don't know what to call them). It is not coming from the point where the fuel line attaches. See the pic below.

See how the two fitting on the left are dry and the two on the right are wet with fuel seeping up around them. Not sure if it is one or both of these two. So what gives, how bad is this??? How to fix?

GregMN · #12 11-07-2009, 05:57 PM

Just o-rings. Get the socket for the fittings and replace all 6 o-rings. If you are going to ever run bio-diesel, get viton o-rings.

Mazootpusher · #13 11-07-2009, 06:00 PM

These are the delivery valves on the IP, there is o-rings in there need replacing.
not bad of a job you will need to have the special socket for removal.

http://www.peachparts.com/Wikka/OM602InjPumpFuelLeak

tankowner · #14 11-07-2009, 06:15 PM

Okay. Thank you guys. I see now that it - is as you have indicated - the delivery valve seals, and that there is a DIY on it for the 606, which is nice. I'll read up and see what else I need to know. Glad to have figured out where it is coming from, a little bummed it won't be fixed today. Oh well.

I have a bunch of Viton o-rings for the fuel lines - wonder if they are the same size. Anyone know? Thanks again all!

TMAllison · #15 11-07-2009, 08:06 PM

There is this write up also. http://www.peachparts.com/Wikka/OM606DeliveryValveSeals

Please clean the IP more than shown and DON"T remove the Valve Element or Colar. Getting those parts out of alignment when reinstalling commonly results in the pump beng sent to Bosch to be recalibrated (~$1000) or replaced. There is absolutely no reason or need to remove either.....

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