After a lot of searching on this subject I thought I'd ask.On my 87 300d I finally replaced my o-rings and washers on the delivery valve because the leak was getting bad.The car ran great before other than the leak.Things seemed to go smoothly all torqued to specs. Started fine and idled fine and no leaks. Backed out of driveway and started hearing a click or knock in the engine and an increased amount of smoke at idle and even more at 1500rpm-2000rpm.Drove around the block slow and the noise was still there.I'm thinking there is an obstruction to 1 of the injectors or mabey I screwed up the torqueing procedure. I will try to retorque valves and hope that helps .If it is an injector what is the easiest way to locate which one(with a tool on the top of each injector to my ear they all seemed to sound the same. Thanks a lot

OK I went and retorqued. As I was taking the fuel line off the #6 delivery valve i didn't notice any fuel leaking out which I saw on each of the others .So I removed the valve and it was also dry .I decided to crank it over and see if fuel would come out and it did.but it drained back down unlike all the other valves which stayed full.I hope this is normal!!

Well it still smokes a lot,and i'm kind of stumped.I'm wondering if an italian tuneup is in order.On some of the delivery valve repair threads I've read it seemed some peoples cars didn't run as good as before the repair(smoking,rough idle,ect)some had to fix the ip timing or the timing chain. Why would this be?? All I wanted to do is fix the fuel leak.Any input would be awesome.

I have noticed that after changing delivery valve seals the OM60X engines will exhibit a quite a bit of combustion knock for a couple of miles. If I were in your shoes I'd drive it 10-15 miles and see if the knocking/clacking improves.

I drove it a bit and tried to burn some of that crap out italian style and the clacking is almost gone,but I think I need to check the injectors.When I bought the car 3 months ago the previous owners(an older couple which owned the car for like 10 years)thought it could use new injectors which i imagine a mechanic told them would clear up the smoke issue at startup.They didn't say anything about the IP leaking but they did think it had an oil leak which was actually the IP leaking.The car used to be a little quieter when I first got it I think.What other things could attribute to the louder engine noise?Or is it just a diesel?

Funny enough, I did the same exact repair on all 6 delivery valves exactly 1 year ago. My car still has a "nailing" sound that wasn't there prior to starting the job. I had a pretty bad fuel leak and I even had MBI in Portland, OR recheck everything. The leak is gone but I still have a "clack, clack, clack" sound at idle and it "pings" between 1000-1500 rpm.. just before the turbo picks up. I've tried Diesel Purge, newly rebuild injectors, etc and nothing seems to help. I am really beginning to wonder if I simply need a new IP. Please keep me posted on what you find as I'm very, very curious and would love mine to run and "sound" the way it did prior to Delivery Valve repairs...BTW, mine does idle very nicely and there is little to no smoke or shaking... just a clack, clack sound.

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1960 MB 190Db w/ full sunroof
1985 Toyota Pickup
2006 Honda Odyssey EXL R&N
2001 VW Jetta GLS TDI

I just finished replacing my delivery valve seals on my '96 and I have the same problem. Now my car sounds like a can of marbles at idle, especially when the engine is cold. I had a similar experience with my ex-'87 300D but that one in addition to knocking more also started smoking and idling rough probably because I didn't tighten the valves down enough. This time though I used a torque wrench and tightened each valve three times to 35 Nm and I did my best to keep the IP internals clean so I don't know what I did wrong. I'm getting the feeling that these OM60x engines are extremely sensitive when it comes to touching the fuel system. After checking the injectors on both cars I also got increased knocking, but on the '96 it went away after some time. I'm hoping the same will happen again this time.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

These posts almost make one want to avoid changing out the seals. There was a post awhile ago where a guy had them done at a dealer and was really upset. Acording to what mercedes service specialist told him was to reset the timing a little retarded. The garage apparently tried it and he was satisfied. Strange to say the least if true. I guess the real question should be what paremeter is changed when you change the seals? Perhaps a good pump guy or shop might have the answer as they must have to deal with this problem themselves from time to time. Two things come to mind. This problem is so common that mercedes should know something at dealer level. Plus move your screwdriver from the injectors to the delivery valve area. Thats where your clack might be. When number six was noticed to take back the fuel perhaps it snaps shut under true load. Kind of binding perhaps. It should not have been backdraining really even at Manual rotational speeds. The other five where not. Perhaps the area being worked on is not cleaned down enough and a little dirt upsets things. But that should wash out. I do not even clean the area in a competent fashion on diesels all the time before removing lines for example. Yet all manufactures want it really clean. The true answers will come with time.

Just finished doing the delivery valve seals on my 96 e300d, and ended up with the same results you got. Prior to the job, engine was quiet at idle, but now it sounds like a diesel...with minor clacking. No problems with smoke, power, performance or sounds at highway speed, just makes a sewing machine sound at idle, or when driving about 15 mph and taking your foot off the throttle. I have read most of the posts regarding this issue, and hope that it will go away with time. The one thing I did notice was the fact that when the engine is started from dead cold, the sewing machine sound will not be present while the glow plugs are engaged. Once the after glow process is finished, the sewing machine sound is immediately noticed. Any ideas would be greatly appreciated.

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96 E300d

The knocking did go away on my car eventually, but it took a few thousand miles. You keep referring to the "sewing machine" sound as if it's bad. Most people including myself refer to it as the smooth, quiet diesel sound that you do want. The opposite of that would be knocking, nailing or marbles-in-a-can sound.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

So there is light at the end of the tunnel. Thanks so much for getting back to me. At the present time I have put about 150 miles on since the seal job, and recently added Lucas Fuel treatment to the tank so we will see what happens. Thanks again!!

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96 E300d

Mine took about 1000 miles (two weeks driving for me) and two DP's of 2 cans each.

My feeling is that some debris from the bad orings gets flushed to the injs when you do this job.

Next time I do mine I'll disconnect the hard lines at the injs and pump some fuel through and into 6 collection cups before re-starting.

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Terry Allison
N. Calif. & Boca Chica, Panama

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

Thanks Terry, I think you have an excellent idea regarding the hard lines. After reading the horror stories about the delivery valve job, I was more than a little bit cautious about doing the job, knowing that I could screw up the injection pump. I kept having this nightmare that I would have one of the springs, which I thought was the size of the ones found in ball point pens, pop out, and have no way of finding it. After doing the job, I think if I had to do it again, I would not be too intimidated. About a week after I did the job, Parrot of Doom came out with his DIY , which was excellent. Thank you all for your responses and ideas.

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96 E300d

Just did the seal replacement on my '87 and I too have the same noisy engine issue. Hopefully it will go away after I have a chance to drive it. I could see some crud from the old O-rings in the IP after I removed the old seals but there was no way to get it all out. I even removed the hard injection lines at the injectors before I started it up and cranked for a minute to try to blow them out but still got the clatter. This must just be a byproduct of the job but would love to know exactly what's going on.

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LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

I don't think debris from the old O-rings is involved as that would probably never be flushed out
DDH

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!