A check every fifteen thousand miles. If you do not know if that recommendation by Mercedes was followed. Plus you found the valves where all pretty tight before you adjusted them.

A recheck is not a bad ideal at say a thousand miles. As carbon might have built up on the seats and gotten pounded off if the adjustment had been ignored for endless miles.

A quick recheck does not mean they need adjustment again. If they obviously really need another adjustment. Once that is done. Check them again in another thousand miles.

*Exactly* what Barry said ~ usually no one has adjusted them for years much less miles so the gaps will tighten up by your next oil change interval, once you check them a few times they'll settle in and only need checking / adjusting about once a year....

Remember : valve check/adjust only when cold engine .

Oil and filter change only when the engine is blistering hot .

The fuel intake screen should only ever be the clear plastic one so you can see at a glance when the crud begins to accumulate .

The translucent ones are worse than worthless because by the time you can see the black crud inside they're pretty much clogged .

Use Biobor or Startron in a prophylactic manner .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Thanks Barry and Nate. My pre filter is the clear type. Clean and clear, no junk in there, yet. I've been using "Stanadyne" diesel additive, (cetane booster and lubricant) but not for any particular reason. In fact, I need to order more, of "something" if Stanadye isnt recommended.

The flapper valve helps performance if adjusted properly.
The valve helps reduce back pulse and helps keep manifold vacuum higher.
A improper adjustment will lower performance as will removing blade.
With a proper adjust performance is increased in all rpm.
Best running of all the 240s.

Some sort of biocide, the two I mentioned are what have worked best for me .

Biobor is the Mercedes recommended one, Startron is beloved my boaters who run diesel engines .

Shop around, I buy by the gallon to reduce co$t$ and it lasts a long time ~ I keep a shot glass in the trunk and ad a full shot to every fillup .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I haven't adjusted the flapper at all. I did temporarily "tie" it in the open position and noticed an immediate decrease in performance. I put it back to "normal". It was mentioned there's a plastic bushing involved with the flapper linkage. I have no bushing on my linkage and noticed the linkage doesn't actuate the flapper anytime in it's travel, from idle all the way to WOT.
I'd be willing to bet the "bushing" is NLA, but ya never know til you check.
Is the adjustment procedure fairly easy to perform/describe, or is it an adjustment of the entire linkage system?
I remember seeing a post that showed all the ball end rods and their appropriate lengths (from the FSM). I'll be darned if I can find it again. I'd venture to say my linkage has been "fiddled with" at some point in the history of the car(plus the missing bushing). I agree, there's probably some "performance" to be gained there, if properly "set up".
Does anyone "out there" have the proper adjustment procedure, or rod lengths? Thanks

There may be missing linkages. One vertical, two horizontal.
easy adjustment,adjust one link so it contacts the vertical link later,has slot in link.
Best performance blade set to 80% at full throttle. Better at all rpm.
Do not think bushing is available,but could be made. Ck wrecking yards.

Thanks for that, herc. Yeah, that linkage, over by the butterfly, is just floppin around in the breeze. It doesn't actuate the flapper in any position. I've got no idea what it's supposed to do, or even look like, when it's "right". Gotta have something to do with my sluggish performance. I know these 240's are slow, but mine seems like its chokin all the time. Kinda like with the old points/ignition cars when the timing wasn't right. (yes, I know there is no ignition and timing on this car) I just get the feeling this car can do better...

Wanted to report the "latest". Put the EGR system back together "as original" to the car. At least, since I've had it. Only difference is the vac line going to the EGR is disconnected and plugged. Test drive had positive results. Car is running better, seems a little quicker both in acceleration and when up to speed. I had removed the pipe from exh manifold to the EGR. Made a metal disc and covered the exh opening and clamped it. I couldn't do the same with the EGR because one of the cap screws was buggered (mentioned earlier in this thread) so I couldn't remove it. Disconnected the vac line, plugged it and let the valve just hang out. I think that was causing some issues. It seemed as if the intake air was causing the EGR to "flutter" making a strange noise under load. Not sure and no way to prove it, and surprised that would/could happen. But, after getting it all back together, as it was, save for the vac line, all is good. No strange noises and car is performing a bit better. BTW, the valve was determined to be fubar with Miteyvac testing. It was always connected to vac since I've had the car. Not any more and the results are great! Thanks to all for direction and advice.

https://youtu.be/1dGAemWtBLQ

Thanks for the link. Never thought to check the "Benzman of Bellingham".... Now, all I need are a few giant cardboard boxes filled with extra linkage parts heh heh! Sorry. Just a little sarcasm. He always has great resources and used parts options and makes maintenance of these cars appear to be so simple and easy. After watching, pretty sure the "bushing", discussed earlier, for the butterfly, is MIA on my car. He didn't go into that portion of the linkage, unfortunately. One thing that occurred to me while watching is that my cruise ctl is inop. Not worried about fixing it right now. I guess removing that rod might be a good idea as it serves no other purpose, right? Less monkey motion. Also noticed, when he actuated the linkage, it didn't seem to contact the linkage connected to the butterfly? Guess it'll remain a mystery, for now. I think I viewed this video when I first got my 240 a couple years ago. Pulled the rods off, cleaned the balls and lubed everything. Might warrant another look, at this point. Thanks

The cruise control rod causes no downside it left in place and you'll play hob finding another one when you decide to fix it later on .

There's a Gent in this forum named Kris who's done the electrical repairs necessary to get your C.C. working again or to remove the surging some of them do, it's been a year or to now and his repairs still work fine, I travel long distances in my old 'Benz a lot and so find the C.C. useful .

It also raised the resale value of the car significantly as most are dead .

Could I post any attachments here I'd include one of the bushing .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I hope you completely block off the EGR with a blind gasket( so even if the butterfly valve moves air can't go into the intake ) and disable it's function as well by putting a small ball bearing in front of the vacuum hose, or just cauterizing the end of it before putting it back into place. This way it looks factory for any inspectors.

However, since it's had 40 years of buildup going on. I would take off the intake manifold and clean it out completely then reassemble the system without the EGR installed and in it's place a couple of blocking off plates

something like this kit below.
https://www.doomsdaydiesel.net/product-page/om617-egr-delete



Or you can just weld the intake and exhaust ports shut

Ok, so, maybe this will "close the thread"? I ended up putting the EGR system back together, as stock (in appearance only, without the vacuum line). I was able to "McGiver" a repair to the "butterfly valve rod bushing". It's the vertical rod, attached to the butterfly, there's a 2 part plastic bushing at the top with a rubber spacer/ring, which was deteriorated (that's what I McGiver'd). The butterfly now opens/closes with throttle linkage movement (which it didn't before, due to slop) it's very smooth and accurate. The car, I'm happy to report, seems to run better than ever. The vacuum line from the EGR valve is removed and plugged. Originally, I had tried to make a metal disc, for the exhaust manifold, to cover that hole and hold in place with the original clamp. That didn't work out too well as the clamp is not designed for that function (that was the source of the "flutter" I was hearing as the disc was leaking exhaust gas under load). The stock "exhaust to EGR" tube is a little thicker than aluminum foil. We had determined previously that the EGR valve is shot (via Mityvac). Someone had buggered one of the mounting screws, can't get it out, so I'm gonna leave it all "as is", for now. I'm gonna check the MB dealer and see if the rubber bushing, for the butterfly linkage, might still be available. Also, as my cruise control is inop, I removed the rod for that (placed in safe keeping). One less double ball end rod for the linkage to drag around for no reason....I think I notice a difference at the pedal (could be my imagination).

That is false information.





That is completely misinformation. Literally nothing you said in your post is correct.


The flap's onlyfunction is to restrict intake airflow to create a higher pressure differential which draws more exhaust through the EGR valve than naturally would flow.


There is zero positive affect on performance or economy, it is purely an emissions control device.