1998 E300, I seems I am beginning to have a small diesel leak as evidenced by the spot on the floor and wetness on the short clear line under the injection pump. I read this is not an uncommon problem so I have the typical questions:

1) Where to get hose?
2) Do all the hose while I'm at it?
3) Pull the intake manifold? I'm sure I have to.
4) Does the hose just slide over the barbs?
5) Once I replace them all and put the manifold back, what is the procedure to get air out of the system.

Am I missing anything? ANy pitfalls?

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03 SLK320
98 E300TD 320k Miles
75 914
02 Suburban

1) The hoses (I think) are a dealer only item, don't forget new O rings. Also, BE SURE to replace the O rings on the pre-filter and the back side of the shut-off valve.

2) I would, you can do most of them without taking the IM off. You may want to do the ones you can and see it that stops your leak and save removing the IM for when you really need to.

3) Only for one or two hoses.

4) They use a weird system to connect. The white horseshoe shaped clips need to be pulled out, away from the hose, to attach. Push the horseshoe in, toward the hose, to remove.

5) You have no primer pump so make sure your filter is full of fuel, it will help if the tank is too. All you can really do then is crank, crank, crank. Crank about 20 sec. wait a minute or so then crank another 20 sec. It should start by the third or fourth try.

Hope this helps.

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Muleears
'07 E320 Bluetec 133K my DD
'04 Jaguar XJ8 VDP, 34K
'10 Hyundai Accent 60K Grocery Getter
'02 VW Golf soon to be on the road again
'97 E300 Diesel Son's DD
'61 VERY tolerant wife

Hampton Roads, VA USA

Gone but not forgotten:
'67 250S 95K
'86 300SDL
'87 300D Turbo, 364K! R.I.P.
'98 E300 Turbodiesel, 213K
'02 S420, 164K
'01 Prius 138K

I wouldn't mind betting the leak is on the engine side of the fuel pump, and not the tank side. Don't replace the clear plastic lines just yet.

Fuel shutoff valve o-ring would be my first guess. Cheap and easy job to fix, 20 minutes at the most. You only need the correct torx driver, and a mirror to see. Its the short black cylinder bolted to the side of the injection pump. Can't miss it, it has a right-angled electrical connector in the side.

Spray the IP and fuel filter housing clean with brake cleaner or other degreaser and go for a short drive. Then look or feel to find where the wetness is comming from. Could be fuel coming down from above (ie: delivery valve seals). Can be deceiving.

When its time to job the work (assuming it is a fuel line or the SOV), unbolt your windsheild washer bottle and flip it up out of your way. Will gain you enough room to reach under the IM unless you have a big belly, short arms, or worse, both.

The fuel lines dont really go bad. They do get yellowed with age making tracking down leaks and bubbles more dificult than when the lines are new and clear. Only the orings "need" to be repalced. If you are going to do one you may as well do them all.

I've posted the sizes/counts previously. Search my name and 606.962 orings.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Thank guys, it's not terrible yet but you are right, cleaning the area will make it easier to see.

I thought I saw fuel around the black cylinder (yellow arrow) which Parrot describes as the shutoff valve. I thought I was seeing the fuel on the line below it, blue arrow .... but that is gravity. Hopefully Parrot is right, and TM, I'll likely clean the area as you suggested and poke around. The lines do look to be in good shape.

The boards experience always saves me time and $ over my slow learning methods.

Attached Thumbnails

 

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03 SLK320
98 E300TD 320k Miles
75 914
02 Suburban

Having messed with leaks in the past on my four diesel cars, my suggestion is to just remove the intake manifold (take the opportunity to clean it) and replace all the clear hoses and o-rings in one shot. The hoses from the dealer come preloaded with the o-rings and they only cost between $7 & $15 each. The o-ring behind the shut-off valve only costs about $2 .... and I'd also replace the fuel strainer and o-ring (about $10) in the fuel canister mount. I've had one clear plastic hose develop a leak from rubbing on a bracket and the locking mechanisms easily break on old hoses then they don't lock down tight. That's why I like to just replace everything at once and then I'm almost guarenteed to have no more leaks for more than 50,000 miles. It's super frustrating to just replace one or two o-rings to have something else spring a leak a month later. It's hard to tell from your picture but your delivery valve seals may also be leaking ..... I'd replace the copper and rubber o-rings in the pump if you haven't done that before. It's not a tough job if you have the right tools and you are careful to follow MBZ directions. There are a number of posts in the forum with pictures you can research. You can't order delivery valve seals from the dealer directly for your engine/pump .... however; you can order them for a 1987 300D Turbo ..... and those are the same that fit your engine. Just my suggestions .... having been in your shoes before.

David Roseman
Long Beach, Ca

Good luck with your fuel leak detective work. It would be in your interests to check & see if the fuel has found its way to the engine mount. If it has, you may have a mount failure in the next few months. Sorry to be the grim reaper, but I thought it best to warn you to be prepared.

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

[QUOTE=TMAllison;2602229]

"Spray the IP and fuel filter housing clean with brake cleaner or other degreaser and go for a short drive. Then look or feel to find where the wetness is comming from. Could be fuel coming down from above (ie: delivery valve seals). Can be deceiving."

I would definitely follow the suggestion posted by TMAllison. I had a similar issue, and the fuel would puddle up in the belly pan. After using the break cleaner, I made sure that the top of the IP was totally dry. After starting the engine, I continually ran my fingers along the top of the IP delivery valve area. The amount of fuel leaking was not evident to the naked eye, but could be felt on my fingers after a few minutes. Replaced the rubber seals and copper crush washers, and that was the end of the leak. Good luck with your repair.

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96 E300d

Cleaned the area with brake cleaner. None of the white clips were pushed 'home' so the bottom of the 'U' was as close as it should be to the ferule. The were not the whole way 'out' or 'in'. Is it possible they vibrated out or were they never homed?

Ran the car and the area is clean. We will check again tomorrow.

It doesn't look dificult to do all three lines with the washer fluid container moved.

How dirty does an intake manifold get and how dificult is it to remove clean and replace?

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03 SLK320
98 E300TD 320k Miles
75 914
02 Suburban

The u-shaped clips on the fuel lines should be loose, in what you would expect to be the "out" position. To release the pipes, they are pushed "in".

Cleaning the intake manifold is a doddle, however it can be a pain to disconnect the EGR as you have to get underneath the car to find one or two of the bolts.

Confirmed weepage at at least the 1st and 3rd delivery valve seal. Brake cleaner, dry with air good, start car and i can see the sign of color change to the top of the IP Housing. Repeated to make sure and yes it is the bigger, manifold off job. So this is what I think I understand reading Parrot's good directions for delivery valve seals:

1) Buy special socket from site
2) Buy crush washers and orings for delivery valves from MB (one is not available but 1987 300D Turbo part works.
3) Buy o-rings for clear lines - MB, don't think I'l go with the line assy but maybe. Mine are clear.
4) Buy shutoff valve o-ring
5) Remove IM and EGR, clean both, IM was done 50k ago should be reasonable.
6) Remove lines to Delivery valve, tag, take pictures etc
7) keep dirt out of intake, delivery valve etc
8) Complete delivery valve procedure, note torque procedure
9) Remove shutoff valve and replace o-ring, careful not to strip torx.
10) replace o-rings on clear lines.
11) Reassemble IM and EGR
12) Pray, Start, 10 seconds max starter, kill battery, pray...

Does that about cover it? One open item is which delivery valve part is the 1987 TD part? Any reason to get Viton o-rings, I don't intend to run anything but Diesel. Other fuel line, what should I use for the braided rubber lines if I decide to replace them?

Merry Christmas, hope it warms up for this job!

Going for a 14 mm box end wrench to adapt now.

What is the recomendation for cleaning the intake ports to the cylineder head?

One line was leaking as it went into the fuel injector. Is that a tightness issue or a seal.

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03 SLK320
98 E300TD 320k Miles
75 914
02 Suburban

All done, observations are as follows:

1) the delivery valve washers and springs must align themselves pretty well or sucess would be impossible. I centered everything as best I could but I know they moved at some point. I hand threaded each delivery valve down until the o-ring engaged so that I could possibly feel any 'problem'. I did not remove the metal lines from the injectors. There is enough movement that a delivery valve can be done individually .

2) it was hard to pull the clear lines, even once releasing the white clips I'm not sure they pushed the black retainers out enough to release the connection. I broke some. The O-rings themselves fit tight and did not release easily. I'm glad I bought the lines not just the o-rings,

3) the manifold and head had approximately 3/32" of tar on them after 70,000 miles. My car gets 30 minute trips as a minimum but probably needs more sporting driving.

4) Hoping the fuel in the injector holes was from the return lines. I replaced them all. The former mechanic had pinched the final return line between the head and the cover so maybe that was the problem.

5) Plan on replacing all the plastic clips. Some of mine were functional (tied together with zip ties), one had no plastic clip and was rigged with two zip ties. The rubber pads were all in tact.

6) My leak, other than the one at the injectors was 100% delivery valve related. The o-rings were in bad shape.

7) No worry about the motor mounts, it seems MB figured out that problem, my car has plastic covers that protect the motor mounts well.

I'll leave the cosmetic cover off a few weeks to see if I have any leaks around the injectors. Thanks for the help.

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03 SLK320
98 E300TD 320k Miles
75 914
02 Suburban

30 days and it looks/smells like the third delivery valve back is leaking at the base again. I did the washers and o-rings and they were torqued right (3x procedure). What did I do wrong? Fuel is standard diesel and they are the OEM O-rings. Looks like the manifold is coming off again and I'll give it another shot.

The star retainer doesn't look like it fits the star on the delivery valve tightly like the others. Is it possible it backed out? Most likely dirt or I didn't get the o-ring sealed corectly?

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03 SLK320
98 E300TD 320k Miles
75 914
02 Suburban

as you mentioned, the o-rings are a tight fit. You need to lube them up and remove any deformation / twisting once they are on the DV holder.

also. "slacken" means to stop torque on the wrench... not loosen the DV holder.

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