They Said it Can't be Fixed - A Journey to the Inside of a Mercedes Bluetec

Quick update on our ML350. It continues to run surprisingly well, and is a very solid handling & braking tow vehicle.

Just finished a B (B+?) service. Changed engine oil & filter, air filters, fuel filter, cabin filters. Also did the recommended 'Extract all DEF & refill with fresh'. 5gals did not quite bring it to full, need to get another 2.5gal cube next time at NAPA. 

The tire that I pulled a nail out & shoved in a string still had a slow leak (4-5 psi/week). The wheels were off to rotate, so the tire was dismounted and a 2" patch was clamped inside on the string repair. Seems to be holding 100% now. The tire repair was free, if I ignore the cost of tire machine.

The one mechanical problem is oil leaks at the front of both cam covers and at the steel sump.

It's messy, but only requires a 1 liter top off at 5k miles. A closer look showed that 90-95% of the joint is sealed. I elected not to attempt repair on the assumption that I would just end up with a leak elsewhere.

A look at the bug filled filters. Yes, the ram-air is quite functional. 

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And a pic from today, at Cowan Lake SP. Tow truck doing tow truck things.

Well, things were going swimmingly until the parish festival.  There is something about the festival that just does bad car things to me.  One year it was emergency tires due to a puncture.  One year my whole family nearly got killed coming back from the festival late at night due to someone coming over a crest at a high rate of speed.  In our lane.  Where there was almost no shoulder.  And then, of course, we can't forget the year that the engine decided that the #2 rod bearing would make a tasty treat.  This year, on the way in to the festival this morning, the left front air strut went ka-bang.  It's an Arnott unit that I put on back in February of 2018, so it "should" still be covered by the lifetime warranty since they didn't go to the 24 month warranty until 2023. 

But...  Rockauto says that the part is out of stock and they can't process a warranty return so they'll just refund the original purchase.  Which means I'd have to buy a new one.  That is more expensive.  And only has a 24 month warranty.  I think they just changed the flipping part number so they didn't have to deal with the lifetime warranties anymore.

In reply to wae :

Have you contacted Arnott?  They may honor the warranty.

In reply to Aaron_King :

I thought about that...  A couple reasons I didn't:

First of all, as it turns out, the new one is basically the same price or maybe even a little less.  So I'm not really out any significant amount of money.

Second, I don't anticipate having this beast for another two years.  At the rate I drive, that would be another 40-50k miles which would exceed the expected life of the transmission - I've got it to 167k now.

Third, I've talked to them before about a warranty replacement on an airbag and they very much didn't want anything to do with me, referring me back to my retailer.

Also, I knew with some level of certainty what Rock Auto would be able to do for me in terms of when I'll get the new one.  I was able to order it last night and get it on the way as opposed to calling Arnott today and taking however long to work through their process and their shipping times.

And finally, the worst reason, after the festival weekend, I'm just freaking exhausted so I the easiest answer is what won!

I will say, though, that the OEM strut is still on the right side.  With 167k miles on it.  And the strut that I replaced with this failed Arnott unit wasn't actually failed - turns out that one was just an oring on the air line that failed, but I went ahead with the new strut because everybody talked about how much better the Arnotts are.  The failed strut has about 70k miles on it, plus or minus.  And when the second OEM spring failed on the rear due to crappy Ohio roads, the replacement bag from Arnott failed within a month.  So I'm not convinced that these Arnott products are all that fabulous.

I can believe the Rock Auto thing.  When I did the bags on the R Class I got them directly from Arnott and in the 100K plus miles I have only had to replace one and they were great about it.

In reply to Aaron_King :

That's interesting... I didn't know Arnott sold direct!  Well, perhaps I'll file that away in case there's a next time!

In reply to wae :

The iPD heavy duty strut mounts for my Volvo sat in the "worn out" position when new.

After 120k or so, one was thoroughly broken.

I replaced it with one of the 220k mile Volvo units that I took out and saved because they sat better than the iPD ones.

In reply to Pete. (l33t FS) :

Did we reach an inflection point where the OEM parts started getting really good while the aftermarket parts just didn't?  Or did the OEM parts stay the same and the third-party stuff just took a dump?  Or is it both?

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In other news, despite creating a label for it, Rock Auto didn't actually give the strut to FedEx until this evening.  So I'm not expecting to get it until Thursday some time.  Which is putting a kink in my plans to go to Oktoberfest Thursday night.

I find that parts quality is all over the map anymore. Formerly good brands like Bosch and Febi-Bilstein and SKF are just as likely to be chicomm junk or made in DE.

OEM parts quality depends greatly on the OEM.

Chrysler parts? Junk parts for junk cars. (Sez this former ChryCo tech) 

Toyota parts? Reliable parts for reliable cars. (Sez this 30 year Toyota tech).

In reply to wae :

Rockauto ALWAYS does this when they ship by FedEx and I don't understand it. I have a strut that's been sitting at "label created" for two days now. 

In reply to peanutpckrupper :

I'm about 75%/25% with them on that - usually they hit or exceed their target.  I would have just bought one locally, but FLAPS wants about $300 more for the same part number to get it today.

In reply to wae :

Yeah that's the fun part with Mercedes, if the FLAPS has it it's usually 3-4x more expensive. 

If I need it quick usually Amazon is my go to. 

Last Monday we were dragging RV trailer home from NCM, and the CEL came on near the top of a long grade, as has happened several times before. Truck ran normally and now after 10 stop/start cycles the light is off. I didn't even bother plugging in scanner to find the usual "undefined" powertrain code. 

I've asked 2 of the 3 Central Ohio MB dealers to look at it, and just document the code so if the engine craps out down the line we have an idea of where to start. But they both say I need to drop it off for a few weeks until they can get to it. Translation: we don't want to touch your ancient vehicle, especially at warranty rate.

Knowing this, I thought it's time to rip up the warranty and delete some stuff. Unfortunately, while I've been futzing around with keeping it stock & running good, tunemyeuro.com has gone under, so there is no reliable US provider of such race prep service.

Humph.. .

It makes my brain hurt a little bit that the "High MIleage Award" is expressed in kilometers....

That's a snazzy looking badge though. 

They were impressed a GL350 made it that far.

eastsideTim said:

They were impressed a GL350 made it that far.

What would be really impressive is if I could get a second one for it - 310,000 miles.  No way that could happen - I don't feel like rebuilding an OM642 again...

It is a snazzy badge though!

Almost to 175,000 miles.  I brought it in for an oil change.

It's blowing a code about the bank 1 sensor 1 O2 heater circuit so I may try another new Bosch unit in there.  There's also something going on with the air suspension in the front.  Sometimes I'll come out to the front right being down, sometimes it's fine.  It seems to be constantly trying to adjust the front height and the compressor is definitely running more than it should.  I think Xentry/DAS can do diagnostic stuff on that so I need to get my laptop, the car, and the OBD2 adapter all in the same place at the same time.

In reply to wae :

Isn't the O2 sensor still under emissions warranty?

In reply to FJ40Jim :

It would be...  But I've put over 48,000 miles on it since the emission work, so it's back out of warranty again

Hello wae, and thank you for this fantastic educational and entertaining thread! Just had to register to comment this, but probably also have a lot of questions about these engines.

I found this thread in the search for torques on the turbo and all the bolts that belong, but ended up by reading the whole tread. It gave me much valuable information on the 642 engine, but also a lot of good laughs  The highlight must have been when you wrote that the car probably during its life had leaked oil on an indian grave, nearly fell off the chair  I don`t know if you use the term "Monday car" in your country, but your car certainly deserves that label (a lousy car where new faults constantly appears). 

About the leaking air in the suspension. A couple of years ago I changed a valve block for the suspension in my car (2007 ML). It is located by the right front wheel, and is not a big job to replace. I bought a new valve block from ebay, think I payed about 150 EUR. Turned out to be a completely different fault, but that`s another story. The air suspension system is not very complicated, I think it has an undeserved bad reputation. 

My challenge is that the car goes into limp mode with two different codes on the EGR valve. In the process of troubleshooting I also discovered that the turbo is defect. It has similar damages to the turbin wheel as your  had, and I think I know why. It makes some nasty noises now... I am planning to delete the EGR function, and as the turbo needs replacing will use the opportunity to replace gaskets on the oilcooler, delete the swirl flaps, and clean up the intake manifolds and the ports on the heads. 

Last, have some patiens with the language, but I assume that you prefer bad English from good Norwegian 

I have a question for you guys. 

In november last year the car suddenly went into limp mode, and I got theese codes was on my iCarsoft code reader:

First I took out the EGR valve to clean it, but I was surprised that it barely was a thin layer of soot on it, not a lot of carbon build up, and the mecanism was sliding smoothly. 

Then I bought a new EGR valve from Autoparts. But before I replaced it I got in contact with a former colleague who is a wiz on tuning, and agreed that we would delete the EGR function, so I returned the valve. 

But as time went the symptomes from the car got worse. It started to make some nasty noises, and sometimes it felt like I had kangaroo-diesel on the tank. Whet I took of the "batwing" to replace the PCV valve, I also discovered that the turbine wheel on the turbo was destroyed. I got my hands on a used turbo that seems to be in good shape, but have not replaced it yet. As I wrote in my last comment I plan to do som more maintenance when I am down there, among other things delete the swirl flaps. 

I guess the reason the turbo is damaged is that pieces of the rubber gasket between the batwing and the turbo have come loos, an then been sucked into the turbo. It looks like the batwing was incorrectly installed last time the diesel filter was replaced. One of the rubber sleeves against the air filter box was also not in place.

Then to my question:

Earlier in this thread I read that some of you had unplugged the MAF sensors, and that the car then stayed out of limp mode. Today I decied to try that, and it worked! I didn`t even get a engine lamp in the dashboard. But of course, I got some new fault codes up (Low air flow etc.) 

So, can any of you explain for me why The car do not go in to limp mode when I unplug the MAFs? The weird thing is that all of the nasty noises also disappeared! My (unqualified) guess is to that is that the noises came from the swirl flap motor, and that it was disabled when the MAFs where unplugged. 

Ideas?

Regards, Thomas

(Lucky owner of a black Scheißwagen )

Not sure about the laws & emissions standards in your country, but in USA a vehicle goes into limp mode to prevent:

1. Damage to the engine or transmission. An example would be an engine going to limp mode because coolant temp sensor reporting 150° instead of the usual 95-100°.

2. Excessive emissions. An example is going to limp mode because of inoperative EGR or empty DEF tank.

It didn't go to limp mode when MAF is unplugged because MAF input is only used to trim the fuel map. It's common on the very similar VW TDI to reflash with a performance tune that deletes MAF input and relies only on MAP, IAT, RPM, TPS. 

FJ40Jim said:

Not sure about the laws & emissions standards in your country, but in USA ...

There are of course requirements. Every second year we have to go to an approved workshop for a "EU-test" of the car. Among the tests are emissions, but I am not certain of the tolerance limits. However, earlier today I spoke to my former college who does the tuning, and he says that I can delete the EGR, the swirl flaps, and the DPF, and still not get any problems with the limits. Have not decided on the DPF yet, but at least the EGR and swirl flap goes out. 

It didn't go to limp mode when MAF is unplugged because MAF input is only used to trim the fuel map. It's common on the very similar VW TDI to reflash with a performance tune that deletes MAF input and relies only on MAP, IAT, RPM, TPS. 

Thank you very much Jim, this was exactly what I was wondering about! Not that I fully understand all this, but I have some more to get into (I am not a car mechanic, so the abbreviations has too be looked up...).