500E Distributor and rotor problem

[195910]

Just get the price from the
MB-dealer on the caps behind the rotors......
Just around 200usd/each...
I can clean it out for a several time and save “a few dollars” $$$$$$$
/Berglund

Just checked it, 155 Euros each ...Seriously!
Bosch part is exactly the same with the OE number grind off. 40Euros tops.

 

[TerryA]

Just get the price from the
MB-dealer on the caps behind the rotors......
Just around 200usd/each...
I can clean it out for a several time and save “a few dollars” $$$$$$$
/Berglund

@Berglund > Not recommended to clean, sand or scrape off the terminals and it won’t cure your issues. Very temp fix at best. READ POSTS #13 & #28. Klink is a Mercedes Master Mechanic for many years. I and many others here believe what he says.

@195910 > Show us more pics of your new Bosch distributor cap for comparison to gsxr’s

lol

 

[JC220]

I dont understand the need to create a new thread on this topic. It has been covered may times on this forum. Indeed by creating a new thread it brings up the same points as before over and over again.

I would suggest that the mods might create a Distrubuter Cap super thread which combines the 3 or 4 main threads on this very subject.....

 

[195910]

@Berglund > Not recommended to clean, sand or scrape off the terminals and it won’t cure your issues. Very temp fix at best. READ POSTS #13 & #28. Klink is a Mercedes Master Mechanic for many years. I and many others here believe what he says.

@195910 > Show us more pics of your new Bosch distributor cap for comparison to gsxr’s

lol

Per Terry's command, here is a close up of the distributor cap I received

I can post more pictures on the Red Baron thread so we don't hijack this thread

 

[gerryvz]

It would be helpful to create a Wiki page that includes close-up photos of the top and inside of each brand's caps and rotors. That way a comparison could be made in a setting made for it.

 

[Berglund]

Yippee!!!
Today the new Bosch Distributor and Rotors arrive.... about 220usd including shipping.
A German delivery Primakfz.de from eBay.
Date on the Distributor is October-18
Just under half price from the MB dealer,
or a ordinary parts-shop her in Sweden.
Attached some pictures below
/Berglund

 

[gsxr]

Make sure to also replace the insulators at the same time you change the caps+rotors...

 

[195910]

Yippee!!!
Today the new Bosch Distributor and Rotors arrive.... about 220usd including shipping.
A German delivery Primakfz.de from eBay.
Date on the Distributor is October-18
Just under half price from the MB dealer,
or a ordinary parts-shop her in Sweden.
Attached some pictures below
/Berglund

Hi Berglund,

its the same production as the one I received. I can seem one of the terminals has ridges as well. Can you post a close up of the terminals please.

 

[Berglund]

Hi,
Now I have take pictures on the terminals, and yes it’s some small ridges as well.
I look on the one in the car, also Bosch, produced -06. Some very small can I se there also, but it’s used I can tell

 

[195910]

Hi,
Now I have take pictures on the terminals, and yes it’s some small ridges as well.
I look on the one in the car, also Bosch, produced -06. Some very small can I se there also, but it’s used I can tell

Thanks Berglund, Yes this looks exactly like the one I bought.
I guess this is a new method of production

 

[Berglund]

Yes I agree.
We must hope that the ignition pulse finds its ignition ️sequence anyway, and does not "dance around" as they please.
we would get a bit bumpy on the engine, no "beat feeling" directly

 

[Berglund]

And today the Bosch caps arrive with the post-man, now engine up and running again., hasn’t start it up after the New Year’s Day!!!
Missing the V8 sounds!!
Som different old/new caps I believe

 

[195910]

And today the Bosch caps arrive with the post-man, now engine up and running again., hasn’t start it up after the New Year’s Day!!!
Missing the V8 sounds!!
Som different old/new caps I believe

Yup, you are all set now, did you start it up ?

 

[Berglund]

Yes!!!!! I did and enjoy

 

[northNH]

Regarding distributor caps, I just received a new Bosch cap for my 300CE 3.0L M104...
Compared to earlier produced caps (Germany), the new one (Spain) does show the same (functionally insignificant) sloppy tower ridging as noted above with Bosch 119 caps.
Though unlike 119 caps, these are still nice and shiny smooth inside...

And FWIW, for this Bosch cap (and rotor) from Amazon I paid 2/3 of what everyone else wanted...

 

[sadey1992]

I think Doduco is supposed to be the best brand, if you can find them.

Found some through my local Mercedes Benz dealership. They're pricey, but if they're as good as I keep reading here on these 500E forums, they'll be worth it!

 

[ArauzMotoring]

Found some through my local Mercedes Benz dealership. They're pricey, but if they're as good as I keep reading here on these 500E forums, they'll be worth it!

This thread has no one talk about the vent slot mod for the distributor caps!!

Maybe check it out and do that while you’re at it… lol

 

[gsxr]

This thread has no one talk about the vent slot mod for the distributor caps!!

Maybe check it out and do that while you’re at it… lol

Yup! That thread showed up about a year later. Here's the link:

FYI Thread 'Essential M119 Ignition "Tune Up" mods [Distributor cap vent / slot]'

Jul 18, 2021

Moderator edit: In addition to cutting extra vent slots to reduce/eliminate condensation inside the caps causing misfiring, oil leaks must also be completely eliminated from the cam solenoid and exhaust cam seals. If there's the slightest trace of oil at the lower edge of the cap, this misfire issue can still pop up occasionally, even with the slotted caps. Read this entire thread. A related "How-To" thread is located here that is also required reading....

• JC220
• Replies: 58
• Forum: M119 Engine

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[gerryvz]

Another resource that could be of assistance for this:

Thread 'HOW-TO: Solving M119 Stumbling at Ignition Distributor Caps'

Sep 5, 2025

It is a common malady to nearly all M119 engines with dual-distributor systems, sooner or later, that the engine will suffer stumbling and cutting out. This condition is because there is inadequate air circulation inside the closed environment of the distributor caps, which causes condensation to form inside of the caps, effectively electrically "shorting" the flow of electricity to the spark plugs inside of the cap.

There is MUCH more background about this condition here on the forum, in this thread: FYI - Essential M119 Ignition "Tune Up" mods [Distributor cap vent / slot] | M119...

• gerryvz
• Replies: 28
• Forum: "HOW-TO" Tutorial Articles

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[landspeed]

I can attest to that great vent mod for the distributor caps. Worst I ever get is maybe a few seconds of stumbling, a quick rev and it's gone. Going strong for 4 years. I have done the same to some other cars too, with great results.

 

[rayhennig]

that great vent mod for the distributor caps.

I've read about that for the V8 engines. Apparently it works but I have no experience as mine's a 300-24.

But I do have experience of new parts bought from 2019 onwards.

Bosch cap and rotor were installed by some cowboys - didn't need them but they fitted them anyway. Bosch cap was cracking around the central electrode after about 9 months. Binned the cap and rotor in favour of MB - also Bosch and also made in Spain but of a clearly visible increase in quality. I fitted these and coil, shield, plugs and leads, all MB original, and have never looked back. Costly? Yes but I'm much more confident having blown 3 EZLs between 2019 and 2020.

So, I feel that Bosch and MB Bosch are NOT of the same quality.

As an aside, we also needed a new MAF for a 1994 E280T. Steered clear of Bosch and went for a Pierburg insert. Working well.

RayH