using the power steering pulley nut is a lot easier if the glow plugs are removed. Since a valve adjustment is a 15k miles maintenance procedure (OM617A) that works out to yearly to every two years for most daily drivers. Probably a good time to check and ream the glow plugs anyway. Thats' what I do.

Seems I have to revisit this job tonight, as I must have done something wrong.

After the valve adjustment and the diesel purge, Betsie stumbled for a few seconds when I started her cold this morning. As if there's air in the fuel line or one cylinder wasn't firing properly for a few seconds...

Well, just checked the car during a quick break at work, and...I am leaking both oil and fuel pretty badly.

The fuel leak comes from the top of the spin-on filter, and it seeps from underneath the head of the 24mm bolt (pretty badly when revving up actually) and the oil leak I haven't been able to determine yet...Except that I am leaving quite the oil stain right now and the oil on the dipstick was reading too low, whereas yesterday the oil was half-way between low and full, and I have never have had to top of the oil in between oil changes before... Something's terribly wrong here.

*sigh*.... I think I know what I did wrong with the fuel filter, so I am not worried about the fuel leak.

The valve cover leaking, I am not sure what I did wrong there. Nothing is pinched in between. I'll pull the cover tonight and take another peek: perhaps I over tightened the nuts for the valve cover? I used an expensive genuine Mercedes gasket, so it can't be the gasket I'm thinking...

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

Those stupid valve covers... One thing that helps is to really drop the valve cover with gasket onto the head a few times to seat the gasket. But, mine still leaks even after torquing properly and all that, so I'm going to be trying the mod where you file just a little off the valve cover where the stud holes are so it clamps more. Reportedly it'll never leak again. Should've had 6-8 nuts holding it on in the first place instead of 4.

The fuel filter nut might just need new o-rings. I got the Dorman metric o-ring set that has both sizes in it if you have that style of filter bolt. There's also the kind that has a crush washer. Either way you don't need to really crank it down, but it may need to be snugged up.

-Rog

Thanks Rogviler. I think what I did wrong is that the old filter had a thick rubber gasket around the opening where the bolt goes through. I assumed this was part of the car, and not part of that particular filter, so I put that little thick gasket onto the new filter as well. I remember thinking: "Hmm, would this be right?". I guess the answer is no, and I'm confident that when I remove that thick gasket between the bolt and filter my leak will stop.

As far as the valve cover goes: How tight should that thing be? When I loosened it up for the valve job it was pretty tight.
I am used to valve covers being on just a little past hand tight. That's how I put the valve cover back on my Mazda, I hand tightened everything, then gave all a quarter more turn.

Should I do the same on the Benz, or would that be too loose?

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

The torque is about 15 ft/lbs, although it's not so much about clamping force, since the stud has a shoulder on it that prevents the valve cover from going down past a certain point. Hence the filing trick.

Definitely try to get it to seal as it is if you can. Once you start doing mods, everyone FREAKS OUT.

-Rog

15 ft/lbs....Yeah, I don't have a torque wrench, but that sounds like "finger tight + a quarter turn" to me...

Which means I overdid it last night, since I went by how tight the bolts were on there in the first place...I'll check the whole gasket tonight to make sure it's on there proper, and re-do the nuts.

It didn't use to leak, and now it's leaking like a sieve, so it must be because of something I did. Let's just hope I did not damage anything permanently...

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

I presume you figured that "bottom nut ccw" tightens it.

I have done many times and didn't bend any wrenches. I don't have any trouble swinging regular wrenches between the injector tubes. I recall they are 14 mm. If you don't have 2 metric sets, I recall a 9/16" fits fine.

It is finicky trying to tighten the jam nut without changing the gap. Try to hold the top nut fixed and just rotate the bottom. Hopefully, the valve stem won't rotate as you tighten. Always verify the gap when done.

__________________
1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

Double-check, sometimes a wire or boost pressure line gets trapped.

Some people can get the 15 ft/lbs by feel but I bought an in/lb torque wrench because my "fingers" are way off calibration. Usually too tight.

If you will notice, there are a few ridges on the face of the gasket. I'm guessing that overtightening kind of defeats those ridges. The other "trick" mentioned here is to recheck the torque after the engine is warmed up.

Aviation gasket sealant on the head might help as well, if you still have a leaking problem.

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Sam

84 300SD 350K+ miles ( Blue Belle )

I learned on poly locks on a 327 Chevy engine. Strange enough, the learning curve was steep on my first try with a 617.

I'd like to know why those valves tighten up unlike the chevy's solid lifters which always seemed to loosen.

__________________
84 300SD
85 380SE
83 528e
95 318ic

is overhead cam so wear tends to tighten clearances.

Specification for cam cover nuts is: 14 Newton-meters (Nm) or 10 lbs/ft. Overtightening will definitely cause a leak.

I don't think use of a gasket sealer is advisable. I use a thin coating of ordinary heavy grease, such as wheel bearing grease or Vaseline to hold the gasket in place while assembling to the head.

I used an original Mercedes gasket, and it has a groove on one side of the gasket, so you can easily put it on the valve cover and it will hold itself in place just fine.

Unless that groove is supposed to mate with the top of the engine, in which case I put the gasket on wrong side up...?

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

You put it on correctly. I over-tightened the cover several times before I figured out a little too much is too much and makes these gaskets leak.

I have tightened the gasket and trapped vacuum lines several times before I figured out to disconnect them and tie them out of the way. I tried wiggling the valve cover through the complications until I realized the easy way is take an extra bit of time and clear a path.

__________________
84 300SD
85 380SE
83 528e
95 318ic

Since the Factory Shop Manual clearly shows the valve being pointed at the One o'clock position, when looking from the front of the car, as compared to the 12 o'clock position.... only people who can not read a clock face would put it at 12 O'clock.
They look at the lobe... think " one hour away from 12 noon is what I need.....but I do not know which side of 12 noon the ONE is on... so I will just put it on the 12 noon and that will be pretty close... I will assume the base of the cam under the lobes is exactly round.... I will pray they are exactly round...and I will go out and convince other people that it does not matter whether the lobe points to one o'clock or 12 noon..... That is the only reason they could have for ignoring the specific FSM instructions showing the lobe pointing to one O'clock.

The Factory Shop Manual SPECIFICALLY FORBIDS the use of the power steering nut to turn the engine over because that is a tapered connection and you can ruin it by over torqueing it. Over torqueing it makes it into an ' interference fit'... not what you want when you need to service it.

But using the power steering nut ,instead of the specified crank nut, is perfectly ok because you may not even own the car when that needs to be taken off... I have told in the archives what a problem it was getting TCane's pulley off his which had been overtorqued..... several hours and I do not know if it was usable when we got through. Just because the people who made the car wrote the Factory Shop Manual does not mean they really know anything about properly servicing the car.

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I don't like having my belts tight enough to turn an engine over with the PS nut. I made a mistake and tightened an alternator belt too much when I was young. I had the pleasure of replacing both the front and rear bearings in that unit within a month.

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84 300SD
85 380SE
83 528e
95 318ic

@Leathermang

Allow me to open up a big can of worms here, but where exactly does the factory manual say you can't use the power steering nut? On one hand are the folks that say you can use the power steering nut just fine, on the other hand are the folks that say it's strictly forbidden... I understand the reason for not wanting to use the power steering nut, that makes total sense. However, looking at the FSM I see a warning about the camshaft sprocket, but the power steering nut isn't mentioned?

This is not to start some kind of a flame war so don't take it as such; I am genuinely interested.




Following the valve-adjustment how-to on DieselGiant, I did use the power steering nut, and I found I can rotate the engine easily and without using all that much force using the power steering pump.

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)