Toomanybenz, you are right. I am making an irrelevant comparison; however I will still hold that my car is louder than its supposed to be until I drive another similar 300D etc. My starting has also gotten worse since the recent long trip.

https://youtu.be/n46PMl9XSTo

Here is a video of the starting sequence from this morning, outside temperature 75 degrees.

Yeah, that's not good. Glow plugs, a 13 second light, (yet a smooth idle indicates operating GPs) or compression as you mention. Adjust the valves too.

If you can get a SPL meter, that may help with a comparison, I'll try and get one of mine.

Hard to tell, but there seems to be a deep rumble, not really an engine issue tho.

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83 SD

84 CD

Well I am not sure where to start this reply because now I see we have starting issues....maybe just come up for a week vacation...the car could use the freeway driving

I am going to say I was like you when I got my euro, I had a Dodge Dart that was gas and was looking for something a bit better on fuel....I discovered my grandmothers neighbor who passed had his car sitting in the carport still....it was a Mercedes....

Everyone warned me the "care" these cars required....the whole you realize Daimler name the car after his daughter for a reason...right??

This model car is designed more after the W115 chassis from the previous years. This is what I learned...

You can FORGET anything on these forums that is written/posted by an owner of a post 1979 W123 or 300D/240D..

You see I made the mistake of asking the universe for a car that got better gas milage, that was safe, realible and more modern then my green 70 v8 dodge Mopar....I was looking into a volvo...

Then we had my euro/82 I had helped the pervious owner put a battery in the car years ago before I could even drive...I think that is when the car got a taste of my blood

After a short talk with his daughter....we pushed it in front of my grandmothers and she told me give her 300$ when ever I could...

Now the adventure started in the W123...Mercedes built cars...

That is getting close to ten years ago....now I know both the manual and automatic non turbo w123's like the back of my hand!!

I really am saying all this because you may just need to step away from the car for a little bit....These are BIGGGGGG time hobby cars, they are amazingly great cars! but....

Owning one of these cars is like a marrige!

I relay on both my cars for ever aspect of driving now....but it took me a LOT of hands on experience and lots of hours of just reading and reading and reading...

So to your questions....what I see is happening is that you are attempting to juggle to many repairs at once...that just aren't really needed at the moment.....

Your doing an excellent job on being able to fix things but you may very well be damaging other things by not learning the purpose/design of what you are attempting to repair...

Learning the reason why these things were designed the way they were will give you a great upper card on diagnosing..

The rod you adjusted or any bowden/pressure rod/cable shouldn't be adjusted on the first course of action on a repair....

This transmission LITERALLY uses paper inside the transmission....the transmission is so delicate that even the manual urges the owner to use leather on the dip stick...

Now on that rod you adjusted there is a bushing that literally no one on here knew anything about and very little was out there about it. With the clues I tracked down the bushing that is required for the rod to properly attached to transmission with out this the shifting is hard and harsh.

Part no 1102770550
Overfilled transmission......

Now with that out of the way....

The only linkage that really needs to be adjusted and seems to get mis adjusted...is the linkage from the injection pump to the stop lever...

When that rod is disconnected from the stop lever and the stop lever pressed there should be a gap between the top of the rod to the ball of where it attaches of 16mm I believe...

Now we have the starting issue....well there is a lot that causes that as well...

This year came from the factory with a lower power starter for warmer climates....mine had the original...

The loop style glow plugs are the old way of pre heating the engine...these have many faults...and should be upgraded for better starting to Bosch 80035 plugs...

I cannot see photos of your engine but some people have upgraded to Monark brand plugs...well they are crap unlike the nozzles...

Have the battery cables ever been replaced?

These are known to swell with corrosion and should be upgraded to 2 gauge cables...

Also bad ground points can lead to a host of other issues....

Despite what blogs say about these cars and all the amazing reviews from when they were first introduced....these cars do not age well at all!


Out of all honesty I love both of my cars but just sitting here thinking about all the parts that I need to replace, things that need repair and future items that should be replaced to keep the car unstoppable...

I wonder if I shouldn't look into a Honda...

Mind you that yesterday I was just chripping the tires on the euro burning out in the parking lots...

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TooManyBenz, I have been meaning to upgrade the glowplugs but havent because I prioritized other things (maybe wrongly so) etc. I cheated the start a little, it idles quite rough in the morning when I start it for the first time unless I cycle the glow plugs at least twice at least (now that its warm). I usually hold down the accelerator a little bit, enough to raise the idle a tad - kind of like the idle control cable. Its become second nature now since I ve done it so many times. Valve adjustment tomorrow, fingers crossed.

CoolJay, I completely understand how owning these cars can be a marriage. I am an active professional musician and it seems in the past 8-9 months, I read about and tinker with my car more than I play guitar or write!! Reading through the forums have allowed me to trouble shoot a lot of basic things that were wrong or broken that I just couldnt leave untended. You are probably right though in assuming that some of my attempts while good intentioned might be/have caused problems somewhere else.

I think at the moment I will check/adjust valves, change filters, diesel purge and adjust all transmission/throttle linkages to FSM (found a thread where someone posted PDFs' of transmission adjustment pages) lengths as well as the fluid level. My transmission fluid smells like tranny fluid still and isnt discoloured or burnt etc. though I will mess with the level tomorrow. Found that bushing you mentioned, will order it soon. A trip out would be fantastic, although it looks like you are 8.5 hours away - which is more like 9-10 in my car
Nonetheless I would love to witness a non-turbo 300D chirp the tires or one with an interior like yours. I followed that thread and totally got the itch again.
Will keep everyone posted on tomorrows development.

In the mean time, here is a video of my drag race against a bus, which I won....just
https://www.youtube.com/watch?v=HnyTmQ0HcIw
It wasnt full throttle, more like medium throttle. There is a specific amount of throttle that results in the smoothest and quickest shifts and its not full beans, I ve subconsciously adjusted to the cars behavior, which is why i never really notice the awkward changes at all other amounts of throttle.

Seems as if you do have a GP issue, once you upgrade, should be fine.

Yeah, you seem to have numerous issues, one at a time.

I forgot to film a start this morning.

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83 SD

84 CD

I wouldn't mess with the level!

I would order the filter kit, can even get it at a local auto zoo, no pick up tube and I would get 7 quarts of Dex/Merc transmission fluid...

Go out to the car, drain and drop the pan, drain the torque converter and follow on of the oil cooler lines from the radiator to the transmission and loosen one of those bolts...that will drain the cooler....

Now you can pour 6 quarts in after its all button back up and go for a drive....once the temp gauge registers 175 stop, leave the car idling in Park and check the level should be damn near perfect...

Now I wouldn't worry about that anymore and move on to shifter/link bushing inspection/replacement and then move to linkage adjustment....

This would fully service the transmission and hopefully it will be running as designed unless something internally is worn..

Here is a PDF for the change of the fluid as well as torque specs..

http://www.marekv.ee/MB/Automatic_transmission_fluid_and_filter_change.pdf

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ToomanyBenz - Yes, unfortunately it would seem I do. One thing at a time indeed. Looking forward to your cold start video, maybe even an acceleration video too if possible?

Jay - thanks for the PDF and the advice. Didnt mess with anything today but will do tomorrow.
I now realize, my panic in hearing the knocking sound led me to try things that probably didnt need messing with. My valve re-adjustment seems to have made the car perform worse somehow.
I do have some questions for you experienced 300D-ers, Is it possible for injectors to perform worse and cold idle to get worse after long trips ? All this madness seem to have begun after I got back from my recent long trip. The rough idle first thing in the morning the day after is what led me to discover that secondary knocking sound which scared me. Is this normal? Did I panic for nothing serious and cause more harm?
Also, should I swap out the nozzles in my injectors after I have fixed more urgent issues like tranny and valves etc?

Also, can any one here explain this? https://www.youtube.com/watch?v=45yrWYbT_rM
Looks like his shift points are different from mine. I understand that the new nozzles and valve adjustment helped the power, but the shift points seem very different from mine. Were the transmission from 1980 onwards different?

Don't attempt to rebuild the injectors yourself...you'll more then likely end up with more problems then solving....Send the injectors to member jamesdean...

How are you adjusting the valves? Or should I say how are you inserting the feeler gauge?



Whats happening is your driving the car....like a car...and well the Sh**** hits the fans then....because now that it is seeing service and regularly driving your cleaning out the engine and thus revealing more issues...it had happened to both my cars....

A 1981 uses a different transmission....that car would probably have just the vacuum adjusted transmission.....the transmission in your car was only used for two years in the w123....used in 1978, 1979...and well 1977/76 models if you can locate one here..

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Hi everyone, just did the valve adjustment with the supervision of my local indy mechanic. Its significantly quieter and smoother. The power seems about the same, maybe a little better but it could be psychological. Either way, the deep bass throbbing from the intake seems to have subsided, guess it was poor valve clearances. For the sake of my sanity and my cars existence, I will leave all adjustments and repairs alone for a bit. Have some pencil style glow plugs on order, it ll be a week before i get them and probably another till I get around to changing them. Until then, thank you all very much. I m sorry for panicking and inundating you all with questions and long winded messages. Its a hot day so I ll give it all a rest for now, I will start her tomorrow morning and make another video of the ignition sequence and cold idle etc to see how things are and post it here.
Thank you all very much.
toomanybenz, I m still hoping you make a couple of videos.

Actually JamesDean is our resident electronics guru.

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

I hope you ordered the Bosch 80035 plugs.....I have heard nothing but horror stories about the monark alternative!

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Yes Bosch 80035. I did some research on all possible options before ordering. Not too many options available anyway. There was a cheaper brand the name of which I can't remember but I figured go with Bosch even though it was more per plug etc. I think I ll take everyone's advice and do one thing at a time. Now that the valves are properly adjusted, I will do the glow plugs next. Followed by the injector rebuilds. For my sake, I won't set a time line on these since rushing seems to start the downward spiral. Thank you everyone. Video coming soon.

Jay, that diagram clearly shows the error of my ways. I was checking the clearance at a flatter angle, thus increasing the contact area on the feelr gauge. Today's check revealed that every cylinder was too loose.