Hoping to get some ideas. A friend asked me to look at her 98 E300 after a local shop quoted her $1500 to replace the injector pump due to a fuel leak. I went over today and had a look. The leak is obviously coming from the shutoff valve. Appears the valve is leaking through the electrical connector. She said the shop just replaced the valve and O-ring. I am positive the fuel leak is somewhere on the valve, and knowing the leaky EHA symptoms on the gas burners with CIS, I am highly suspect of even a new shutoff valve. I also know it's really easy to nick or pinch an O-ring.

My plan for now is to order a new shutoff valve O-ring and all three plastic lines to the shutoff valve (like $35 worth of parts, so not a huge gamble). If the leak persists, then a new shutoff valve ($160).

Anybody else had to deal with this before I order parts?

I had to have my SOV replaced. I realized I had a problem after parking the vehicle and it sat overnight. I came out to my car in the morning and there was a large puddle of fuel on the driveway. Mechanic identified it was a leak with the SOV and repaired it. I can't remember if he just did a seal or replaced the whole thing.
I think you have the right train of thought to fix it. Start with the seal. If it persists, replace the whole thing.

__________________
Ed
-1984 Mercedes 190D 2.2 5-speed gray market(bought@30,000 miles) (Sold back to original owner@170,000 miles)
-1999 Mercedes E300DT (245,000 miles)
-1999 Mercedes S500 Grand Edition (80,000 miles)

Thanks, Ed.

Sounds like a solid plan.

There are a total of 6 plastic fuel lines in that area. They are supposed to be clear - if they are a dark brown in color, they are very old and should be replaced. If this is the case, it's best to replace them all at once rather than just the 3 you mentioned, as it's about the same labor either way. The new plastic fuel lines come with new o-rings already installed.

This maze of plastic fuel lines and o-rings is a known weak link on the om606. Since they're inexpensive, some folks replace them all every few years as preventative maintenance.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

I have a '98 E300 and have replaced the fuel plastic fuel lines twice. The first time was simply because I had the intake manifold off to replace the glow plugs and did it because the lines and shut off valve were exposed. The second time I really had a leak; it was from a crack in the shut off valve.
1. The shut off valve is attached to the injection pump with torx headed screws or bolts. I needed a torx socket to remove it. I bought a Craftsman EVO socket set (7 sockets) for $12 or $15, can't remember which. The socket that fit was adequate for the job.
2. There are only 2 O-rings that you have to buy. One is where the s.o. valve fits into the injection pump; it is black and about the same size as the one for the pre-filter. I understand that that is the O-ring that most often fails. The second is a small lime colored O-ring that is on the banjo bolt that holds the plastic line that goes from the s.o. valve to the fuel filter. Be sure to buy one of those it you are going to replace that plastic line. All of the other O-rings are already installed in the plastic lines.
3. I think it would be easy to mix up the lines and where they go into the s.o. valve. So be careful.
4. My leak looked like it was coming from the electrical connection too, but it was from a crack in the valve. From what I have heard, the most likely source is the O-ring between the s.o. valve and the injection pump.

I agree with Torsionbar. Replace them all. My recollection is that I paid more than $35.

The lines actually are nice and clear. I'm going to replace those 3, just because they will be off once I get the valve off. Given where the fuel seems to be coming from, I'm thinking this valve may be cracked, as mentioned. Is there and release catch on the electrical connector, or does it just pull off. Always careful not to get too forceful with the plastic parts on these cars for fear of the old brittle plastic breaking.

Her dad is a doc, so the car has been very well maintained since bought new. She asked me to look at this since the quoted $1500 repair was about half what the car is worth. He gave her the car last year and she loves it. She has a 2015 Mercedes and likes the E300 better.

The connector pulls straight off, and it's keyed, so you cannot reinstall it incorrectly.

__________________
1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

Thanks for all the suggestions. Parts installed yesterday. Literally a 30 minute job, including new hood struts and a couple of missing plastic rivets on the grille. Lost about 1 1/2 gallons of fuel in the process, messy but simple job. Car was on a downhill grade, so bleeding on first start was no issue. Car started in just a few seconds, died once, second start ran perfectly. First look seems to indicate the leak is fixed. Going to drop by in the next few days to check it again, but I think it's fixed. Will update soon.

The 2 lines on top of the **** off valve have white colored U shaped locks, how do you remove them to get the 2 plastic lines that go into the top of the shutoff valve to release?

__________________
Currently Driving
2006 E320 CDI
1999 E300 Turbo Diesl
2002 ML500
1995 E320 Station Wagon


MBs I've owned
1997 E320 Assassinated by Pine Tree
1987 300E Wife Killed Engine
1981 300D Stretch Limo Total Loss
1970 250 Coupe 212,000 mi.
1974 450sel 184,000 mi.
1974 240D 377,000 mi.
1977 300D 204, 000 mi.
1979 280se God Only Knows!
1983 240D 130,000 mi.
1972 220D 280,000 mi.
1983 300SD 244,000 mi.

Locks work opposite to what you think. Push them full IN (white loop against the connector) to release the catch ring. Takes some pulling and tugging to get the lines to release. You can seat the new line without messing with the white clip, just push it in until it clicks. I had to look at the clip on the new hose to figure exactly how they worked. You'd think you have to pull the clip off or out, but it's just the opposite.

Looked at it again yesterday. Got just a little fuel on my fingertips when feeling around the underside of the valve. Connector is bone dry. Could still be residual. Told her to drive it a few days and holler for me to check it again. If it is leaking now, it's a drop every several hours, at most... not the pint a night it was doing.

Main side cover on pump , its easy to mistake the front cover bolt for the shut off valve holding bolt, just check it to ensure its tight.

Thanks, will indeed eyeball that. I know I got the right bolts when I pulled the valve to replace the O-ring, but that doesn't mean the previous shop did.

MCallahan, thank you for your reply, I thought the opposite was true!

__________________
Currently Driving
2006 E320 CDI
1999 E300 Turbo Diesl
2002 ML500
1995 E320 Station Wagon


MBs I've owned
1997 E320 Assassinated by Pine Tree
1987 300E Wife Killed Engine
1981 300D Stretch Limo Total Loss
1970 250 Coupe 212,000 mi.
1974 450sel 184,000 mi.
1974 240D 377,000 mi.
1977 300D 204, 000 mi.
1979 280se God Only Knows!
1983 240D 130,000 mi.
1972 220D 280,000 mi.
1983 300SD 244,000 mi.