I didn't know the newer 5 cyl diesels had hydraulic valve lifters. I have a '78,'79 and '80 300SD and they all need their valves adjusted. I did know my '87 300SDL had the hydraulic lifters but I haven't had the valve cover off yet to see what they look like. How do they fit them in between the cam and the valves?

P E H

Thanks!

If anyone has any other suggestions, I would love to hear them. I just called a local shop and based upon my description and tests, they think it may be an injector. I just replaced them about 3 months ago with NEW Bosch injectors.
Help!

Did the shop that replaced the injectors pressure test them and ensure that they are all within 3 bars of each other?

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Chris

'04 ML500 - 53k, Inspiration Edition, Desert Silver
'11 Audi A4 Avant - Brilliant Black
'87 300SDL sold
'99 C280 Sport sold
'85 190E 2.3 sold

One other concept; while the car sits the fuel column leaks out on one or more cylinders. When first started the fuel goes to refilling the column and then goes through the injector when full. The possible ways this leak down takes place are through the injector and/or through the pump element check valve back into the pump.

This last area is one often overlooked. The pump element check valve is sealed internally with copper o-ring seal MB # 004 997 45 40. There is a rubber o-ring MB # 017 997 41 48 that will also need to be replaced. When this seal leaks it leaks the fuel back into the pump and it can not be seen except by symptom. The symptoms include misfires and lean knocking (nailing).

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

stevebfl,
Thank you for your response. Since I just replced the leaking fuel hose, I would like to replace those gaskets. What are the procedures for replacing them? Any words of wisdom or things to watch out for? When I install the new gaskets, do I install them dry or wet?
I would like to try your fix and see if that helps. Everything else so far has not cured the problem.

CJ,

I too tried the leaving the glow plugs on for an extra 20 seconds before starting and still the same problem.

Since fuel filters are so cheap, I would replace them anyway just to make sure.

Do you think you need a valve job? At 171,000 miles you are coming close to needing one. I need one soon and I think that might be the cause of my problem.

I would be interested in entertaining Steve's idea. I will let you know how it goes. I lost your number, e-mail me your number again and I will call you on Thursday.

CJ,

Are you talking about my telephone number? I tried to send you an email, but it gave me a message that I couldnt send it to you via mercedesshop.com.

Email me at ezlife69@hotmail.com. Thanks.

The seals I mentioned are internal to the pump. They aren't especially difficult, although I would consider it the outer edge on DIY repairs. The pump element check valve is held against the pump barrel by the fitting that the steel fuel line attaches to.

One must remove the fuel lines, remove the fitting locks, remove the fitting and spring, replace the copper seal, install the o-ring on the fitting (seal for external leaks), and reassemble. The fittings MUST be properly torqued and one probably needs the special socket MB # 617 589 01 09 00 to achieve this.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Steve,
Again thank you for your insight. I am going to attempt this repair myself. Does MERECEDESSHOP sell the special socket? What is the torque setting? Do the parts needs to be wet with diesel fuel when re-assembled or do they install dry?
Thanks!!!

The rubber o-ring would probably benefit from lubrication the copper one doesn't matter.

As to the tool availability, you will have to ask mercedesshop/partsshop as to whether they can supply it.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

CJ.

Just a thought here. The injectors you replaced were they new or rebuilds? I have had several rebuilt injectors goe south on me, one right from the start the other after a few hours of use.I would be very suspicious of a sticky injector. Even brand new is no guarantee.

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Mark
82 300SD 110k
91 Caprice SS
92 Jetta TD
97 Cadillac Concours(300hp)
84 Celebrity 4.3L diesel

The injectors are new and I pulled them out last night and them bench tested, they are perfect. By looking at the car, it seems that this is what I have to do. Unscrew the line at the injectors, remove the plastic vibration clips, remove the crossover pipe, unscrew the lines at the pipe, maneuver out from under the intake, remove those flat plates that look like they hold down the valves by locking them in the grooves, use the special tool to remove the valve and then replace the washer and O ring.
When you remove the valve from the pump, does everything go "boing" and pop out all over the place? Is it easy to get the washers out?
Thanks again for EVERYONE'S contributions. That is what makes this the #1 MBZ web-site.

there may be a chance of some rust coming up from your tank and blocking an injector on start up. which would be a great idea to fix even if it isnt the case a company named eastwood sells a chemical mix that adds a protective layer to your fuel tank and its pretty cheap go to http://www.eastwoodco.com and check it out.

i still wouldnt rule out the glow plugs yet either, in my car i know there is a glow plug thats not right because my threads are stripped or something one cylinder will keep cross threading the plug and my plug light on the dash only comes on when i turn the key on and it goes out within 10 sec so i would not rely on the dummy light.
also it might be a good idea to check the wiring harness for the plugs for cracks and breaks those wires seem to get brittle fairly fast.
on my model they used a thin steel wire instead of copper and you can hear it crunch when moving the wires around. though that may just be plastic sheathing never the less if the sheathing is gone the wire might be grounding out and one plug might not be glowing causing bad initial startup once the compression hits that chamber that is not glowing properly the car will run smooth again, goes the same with shutting down the car and turning it back on the engine is warm to a point and will kick over instantly and smoothly. a diesel can start if there is only one plug working although rather poorly as you can imagine.

another possibility i can think of is perhaps you need to readjust the idle. what rpm is your car ideling at currently at a cold start-up? should be around 800 rpm's if it is around 600 the car will idle like crap.

if you need to boost the idle up a bit take a look at the fuel injector pump and inbetween the pump and the engine block you will see this big bolt with a nut all the way at the bottom you'll need to loosen the nut and turn the bolt clockwise to boost the rpm's once its purring like you want it tighten the nut back down (thank's goes out to bill lewallen for that tip)

good luck hope you get it straightend out once we get past the little quirks on these cars they make the finest autos out there

jeff