Ok, so background, my dad originally got this car (used) in the early 2010s and I got it when I turned 16. I’m 22 and about to start my final year of college, but these issues started last summer/fall (2025). The car currently has around 223k miles.

The car kept going into limp mode when I was on highways/interstates, so I attributed it to a clogged DPF and did multiple rounds of spray cleaner through the O2 sensor port, and also replaced the E60 sensor (I think). I had gotten a Youcanic device by this time to try and diagnose stuff, but it got to the point where I didn’t feel safe driving it, so I took it home (5 hours away from where I was at the time) and borrowed another truck we have.

I took the DPF off of the car, got it professionally cleaned, but when I put everything back together, we started having electrical issues to the point where I would turn on the car and it would shut off after a few seconds. I couldn’t stay home to work on it so I turned it over to my dad where he started tinkering with it.

He decided to do a DPF delete (which I didn’t want but didn’t know how else to solve the issues), which got the electrical issues to go away, but the car was/still is stuck in eternal limp mode. I’m not sure exactly what he did but I know there is some software component to it, but he never replaced the pipe so it’s just open after the catalytic converter.

We have also had issues in the past with oil leaks so the engine was pretty saturated with oil, so we decided to get a new engine wiring harness and replaced that, but this was only the beginning of this summer, while the DPF stuff lasted the rest of the fall and into the spring where I’m not sure what else he did with the car, other than previous swirl flap motor improvements and glow plug replacements.

After the wiring harness, we did an EGR delete kit which improved the boost a little, but still only tops out at 2500-3000 rpm going uphill without increasing in speed much. I’ve checked the boost numbers before this (I’ve been using ChatGPT a lot), and here are those numbers:

“
* 14.18 psi at 1,400 rpm (you later clarified the unit was psi and that it was held around 1,400 rpm for ~30 seconds). At the time we discussed that this looked like essentially no boost if the scan tool was showing manifold absolute pressure, because ~14.5 psi is atmospheric pressure at sea level.
* I also noted the expected MAP sensor reading with the key on, engine off should be around 100 kPa absolute (~14.5 psi), which is atmospheric pressure.
“

I’ve checked the actuator previously and it seemed to work, but dad went ahead and replaced that, and I had previously hit a branch which shattered a headlight (thanks rain and LED lights blinding me) and (separately) bumped a deer, all on the front passenger side, so he replaced the radiator too.

We also replaced the seals (green and black) for the turbo intake air manifold pipe since the connection with the green seal seemed to have a little leak (visible oil spray after having done a test drive), but we seem to have fixed that, but now he says he hears a leak in the engine bay again near the serpentine belt, but I’m not sure if it’s a leak or something rubbing the serpentine belt since there seems to be a light line near the middle. You have to sit and listen when the engine is idling as it’s not super audible, and the engine is louder than it used to be so it’s harder to hear.

Idk. I’m almost at my wits end and would rather get a new car, but I can’t afford it and he keeps insisting on trying to fix this car when it’s been nearly 10 months out of commission, but he’s also paying for a majority of the “upgrades”. Do any of y’all have any idea what I should do or know anything that could help?

Guess I’ll start with the part where I know how this happened… missed a high RPM shift while racing thanks to my CD009 swap and it’s “notchy” shifter gates and the car had a quick but serious over-rev in neutral. Immediately after pulling off the track I noticed that tick/rattle and if you give it some revs to about 1500-2000rpm it becomes very pronounced. I’ve tried to take videos but due to the natural sound of the motor it’s nearly impossible to hear it on video. It increases with RPM, naturally. Now she literally sounds like she’s purring, lol. Motor was from a donor car I have no history on in regards to upgrades/maintenance. The sound appears to be coming from the middle of the valve cover. I listened closer to the front cover and it does not appear to be coming from the chain/tensioner, but more somewhere up top, but no guarantee it didn’t slip/jump a tooth and wreak havoc. Hoping I didn’t bend a valve or something. I know the springs are also a weak link and prone to breaking and I’m not sure if they have been upgraded.

Me, being the jackass I am… I continued on and finished racing that day and didn’t notice even the slightest lack of power (it’s on an HX45, around 27psi) and she ran just as normal as ever, except the sound. Other than the notorious pulley slip, are there any other known problematic areas with these motors? I primarily work on my LS engines and know very little about these specific engines. I’m gonna do a leak-down test and see what numbers she pulls, probably pull the valve cover and check the condition of the springs, etc… but beyond any noticeable damage, or a failed leak down on a certain cylinder, I would be at a loss. I’m also in the SoCal area, so if anyone knows of a diesel specialist for the OM606 in my area, it would be greatly appreciated!

Hello all i was driving on the highway when all of a sudden i had no power and the engine shut his self down while driving. The filterbox was very hot and smoke came out of it when i opened the filterbox this is what i saw. Ofcourse i was flabbergasted because how is this possible. This side should be only cold the turbo has also failed because all the molten plastic went inside of it and it destroyd it self. The engine works fine when i start it but im scared that when i fix everything it will happen again. Does anybody has an explenation

I’m hoping some OM642 experts can help point me in the right direction.
The issue is a repeatable hesitation/surging under load. In the attached video you can see the RPM fluctuate while my foot is held steady on the accelerator. It’s not a gear change—the RPM oscillates roughly 100–300 RPM and feels like someone is lightly lifting and pressing the throttle.

What has already been done:
Engine air filter replaced.
MAF sensor cleaned.
EGR valve removed and cleaned.
Mercedes dealer replaced the EGR valve and cleaned the EGR cooler.
Transmission service performed twice (once by me, once by Mercedes with pan, filter, fluid, and level adjustment).
Mercedes says it is not the torque converter.

So, i did a injector overhaul myself, everything was right until i put them back in. after driving a bit i noticed a diesel smell in the drivers cabin. when i opened up the hood i saw that the leakoff lines were porous. after i cut off the parts that were done, it didnt leak that much anymore but it still didnt change (yes i also changed the heat shields) especially this one injector at cylinder 3 leaked from the retaining bush (ive also added in a video) does anyone ever had the same issue? maybe i wasnt cleaning them up properly before putting them back in?

I got a few broken hard-line on the fuel delivery. Is there other ways around replacing the hard-line beside sourcing some oem line . Is this a simple flaring job ?

Not sure if this is really relevant to this subreddit but I found it interesting how the MPG changes from winter to summer, as well as the price of diesel due to the Iran Conflict

I have a Mercedes E220 W212 diesel—I believe it's a 2011 model with 170 hp—and I’ve been having some issues lately. While driving, the engine cut out and wouldn't restart immediately. The check engine light came on, and the display showed the thermostat symbol, even though the coolant temperature was normal at 90°C. This has happened a few times now. At the workshop, they read the fault codes and found a "U" error, then reset the control unit. It worked fine for a while after that, but now the problem has returned: the engine cut out again, and the symbol indicating the engine is overheating appeared, despite the temperature actually being normal.

I know the lift pump is the same on some other models like a 190d but I can’t seem to find a gasket anywhere in America . Can I used gasket maker to put it back . One other thing is does the center shaft also spin . I know the pin in the middle moves in and out to pump the fuel but I wasn’t sure about the whole shaft .

Any advice or warnings ? Things to do / not to do or ABSOLUTELY not to do

Been driving a TDI over the past 10 years, and it was the most reliable car I’ve owned. Sadly it met an untimely end.

Is the ML350 pretty reliable, so long as it’s been well maintained?
I’m currently looking at one with 133k kms. The ad says it’s had extensive maintenance and major preventative repairs:

- Timing chain, guides and tensioner replaced
- Oil cooler seals replaced
- EGR valve replaced
- Intake manifold replaced
- Differential serviced

I’ve read that some people haven’t had any issues, while others have. Wondering if the extensive service is indicative of a problematic car, or genuinely proactive.

https://vhr.carfax.ca/?id=31faTPqOPH671U3HBnXBT%2F+145tlvnA7

Asking price is negotiable at $17.9k CAD, and comes with both sets of tires on alloy rims.

Thanks for your help!

Hello group I have an issue with my 2007 w211 280cdi (v6). I mostly drive it like an old man with nowhere to be and it’s quite happy but sometimes I like to give it a squirt. And occasionally when I do I hit some sort of limiter. It bounces at mid/high revs but nowhere near the redline. And kangaroos a bit. But will then continue to drive normally afterwards. Wondering what could be common causes of such a thing ?

Would appreciate any help.

I’ve been losing power and I vaccum test the wastegate , and it only held like 4 inhg. I wasn’t able to give it anymore vacuum because it wouldn’t move pass that mark . I’m sure it’s not normal . Can I retrofit another wastegate to fix this issue and does anyone have other idea of what to do.

I have 2 loose vacuum hose . The first one is a brown hose coming by the brake booster so I’m assuming it’s the ignition line because now my car doesn’t turn off . When I turn of the car it idle low unless I press the mania stop lever . The second hose is a black hardline that is seperated with a brown hardline tha goes to the injection pump and a white hard line that is t into the vaccuum pump .

Picked her up for $2400 and two six-packs of Modelo. (Unpatched negotiation technique)

45,436 is not the actual mileage, the previous owner installed a different speedometer during the engine swap. Said speedometer is also not tuned to the right differential ratio and as a result reads about 10-15mph below the actual speed. But hey, that makes the car feel faster than it actually is!

Anyone that had the same car and can confirm? I know it does not have many hp but it feels too slow and sluggish. I think the dpf is clogged and I want to empty it

i caught the black death super early so do you think my injector will be stuck? i’m debating trying to do the job myself since i just watched legit street cars on youtube do his and it gave me some confidence. or i could pay a mechanic to change them but i don’t know how thorough they would be with the cleaning? and what kind of price would they charge? only one injector is leaking.

Looking for a diesel mechanic or experienced Mercedes diesel enthusiast to diagnose a no-start issue on a Mercedes-Benz 300TD.
Symptoms:
Engine cranks normally but won’t start
Recently had lift pump and fuel filters replaced
Ran well for about a week afterward
Gradually lost power while driving, then stalled
Now starts briefly at times but dies immediately
Suspected fuel starvation issue, possibly related to tank strainer, fuel pickup, or fuel contamination.
Looking for someone who can:
Diagnose the problem properly
Check fuel supply from tank to injection pump
Inspect/replace tank strainer if needed
Help get the car running again
Please message with your experience, availability, and rates. Located in [Portage Indiana].

As the title says, I’m thinking of buying a 300D wagon. I love these cars and have wanted one for a long time. I don’t know anything about them specifically and don’t know anything about diesel engines. I’ve always driven gas cars. I like the sedans but love the wagons. This one looks showroom new. I bought a brand new Lexus last year and it looks as nice as my Lexus. Paint, interior, everything….its all perfect. But I’m wondering if there’s anything specifically I would want to know about this model. It’s a 1980 300D wagon, non-turbo. It has 135k miles on it. That’s the only info I have. I’ve done some research and all I’m finding is that the engine is very strong and lasts a long time. Can’t really find anything else. Does anyone have any info on these? Transmission issues? Prone to rust? Anything at all? The asking price is high at $18k. At least the research I’ve done says that’s high. I’m comfortable enough financially to buy it and maintain it but I’m not interested in something that’s high maintenance. This wouldn’t be a daily driver. Just something to cruise around in from time to time.

Please need help! I’m replacing the water pump on my e420, how can I remove the harmonic damper? Do I need to remove the tensioner or the clutch fan aswell?

FLU 419