Hello I wanted to create this thread because I wanted to get some advice on what service I should perform on my 2015 ML350 with 103k miles to last another 200k miles with no issues. I saw many listings online of the same exact year with 250k miles and higher.

So far whats been done on the car:
Front/rear Brake Pads at 37k
Computer Reprogrammed at 37k
Fuel System Leak repaired at 40k
Steering Gear repaired at 47k
Spark Plugs replaced at 47k
Transmission fluid/seal at 53k
Front/rear Brake Pads at 61k
Brake fluid flush at 92k

I found a local Mercedes only shop and wanted to get a lot of preventative maintenance done. What else should I get done to make the original trans and motor last 300k miles. Thank You Guys!

because you have done maintenance out of schedule (early spark plugs, early transmission service, etc). I would try to resync it to something more manageable, perhaps schedule a 110K miles service to round it to exact numbers:
1 - Due for 60K miles spark plug since last change
2 - Transmission service every 60K/years miles since last service
3 - Brake fluid flush (20K miles since last service or every 2 years)
4 - Check your brake rotors/pads. Yours are wearing too soon, in my experience. On the E350, my brake lasted 106K miles and they were not to the sensor yet, so I could have easily driven @5K more. On the 2012 ML350, just did the front rotors/pads at 141K miles, and the last brake service was @60K miles if I recall correctly. So about the same mileage, though the pads were thinner than the E350 ones.
5 - I would check engine/transmission mounts at this mileage. The 2015 ML is fine @96K miles, but the 2012 is asking for engine mounts (driver's side is shot).
6 - I would check front suspension components: control arms, bushing wear out, and if the vehicle becomes noisy. Also, check the sway bar links (they would start making noise like maracas at some point)
7 - Engine air filter, clean (blow in reverse) it every oil service and replace every 20K miles.

UPDATE: Forgot to mention -> 8 - Differential service at @100K miles: rear, front/transfer case (4matic).

Hey thank you so much for your detailed reply. I want to ask, when you drive you ML does the shifting feel a little rough in the lower gears?? I have been encountering that and I feel like theres a tune or update to fix this?
Also for one sometimes the parking sensor button on the dash turns red (turns off) and doesn't want to turn back on until i restart the car. Then secondly my lift gate would sometimes would not lift up until I try it a second time and then it works as it should.\
What do you think about my symptoms? Have you encountered anything like I have?

I meant to add you as a quote for my other message, just joined today learning everything, lol

I have not had that rough downshift/upshift behavior at 2nd and 3rd gears on either of the MLs, but I recall the E350 had it at 60 K miles and asked the SA at the dealership to do the transmission service earlier (due at 70 K back then). He said they will look into it, and when I picked up, I got engine and transmission mounts (no charge because of the warranty was still valid). Transmission was serviced on schedule at @70K. No issues since, and the car is 106K+ today.

Intermittent behavior that comes and goes with car restarts are, in my humble opinion, due to poor communication between modules because of low voltage, grounds or a confused/hung module clogging the network. Basically, it needs a Ctrl-Alt-Del to reboot the whole car. The E350's transmission was ocassionally hanging "no shift forward/reverse" after a long drive, or "under the weather". Read it could be the SCM, TCM, shifter, etc likely $$$$ cost. Charged my batteries and cleaned a few grounds on the driver's side. It has not done it in @2 years. Cost = $0, though I got a used SCM just in case. I need to remove the EIS and do some preventative maintenance though. Check @CaliBenzDriver posts about all the electricals in this MB generation: W166/W212/W204 (all the same)

Dont forget your;
-front and rear differential fluid change,
-transfer case fluid change,
-coolant flush/fill,
-cabin air filters (3),
-airmatic filter(s) change,
-cam position sensors and magnet pickup -inspection for oil (change if any oil present in wireclip),
-serpentine belt
-check your driveshaft CV joint boots for crack/wear (fairly easy to just replace boot and not entire axle on these...joint comes apart fairly easy).

Thank you for the additional items.

Have you done the coolant drain/fill already? How many miles? If you did, did you replace the reservoir as well? If you also replace the reservoir, did you cut it to see inside? MB specifies 150K miles/15 years.

I just got back from the independent shop and the car is beautiful underneath, no rust at all. I got the oil/filter changed, engine air filter and cabin air filters replaced as they were full of leaves and were dirty. Also got my original 2015 battery from the car replaced all oem. They did however show me that the upper timing covers are leaking. So I'm gonna leave my car there next Wednesday night so they can cold start and see if there is the rattle from the cam adjusters. If there is a rattle, they said we would talk from there. Do you have any advice or suggestions on what to do???

Replace the auxiliary battery if present. Not sure if it was used on early W166. WIS instructions in the GLE W166 section.

Photo of the timing covers? Sometimes the seep a bit, plus oil drips from previous oil services. Unless it pouring oil out of the timing covers, I would clean them up with a rag, brush and brake cleaner. Do not spray harness or electric connector. Then, monitor the cover for a few weeks. Ours are clean at 140K, 107K and 96K. Is the alternator soaked in oil?

So the alternator is soaked when i looked underneath, both upper timing covers are leaking. The independent shop is a highly reviewed shop and told me that the oil can make it through the wires, then up into the ecm module and other issues that can come from it if I don't reseal both. It seems to be just the upper timing covers are leaking as the rest of the car is flawless. I cant tell if my startup has a rattle but it does start unusually loud. they told me it can be the cam adjusters and could be a 2k+ job, resealing it is about 400. What do you recommend?

For sure reseal the front cylinder head covers. Only you and your mechanic can decide if there is a startup rattle that needs to be addressed.

Insect the cam position sensors and cam magnets fornsigns of oil in the connectors. It is almost for sure there with a car this old. Replace the sensors and magnets. Check the ECU connector for signs of oil and clean it if needed.

Definitely leaking front the bottom, or the actuator seal.

Now, a mechanic that tells me the oil leaking through the timing covers edges, or through the actuator seal can make it to the ECU will automatically loose complete credibility with me. The oil in harness issue has nothing to do with this kind of leaks, but oil through the physical plastic of the actuators, the plastic of the camshaft position sensors, oil pump solenoid, and possible other similar component. You can have oil in harness issue w/o a single visible drop oil outside until it is so much oil in the connector the connector will leak it out.

Since the timing covers will be already out, I would definitely replace the chain tensioners just because it shouldn't be much more cost wise.

Since the VVT are also visible, worth doing a manual test to check if any VVT is already failing.

Check every connector for oil in harness. For a 2015, it can be hit and miss. We have 3 of these engines (2012, 2014, 2015), none have leaked oil from anywhere, timing covers, seals or through the connectors. It can be weather related due to the seasonal cycling. Ours are Florida based, i.e. narrow temperature range that North based vehicles.

My 2c

Quick question, so I had my upper front timing covers which were leaking for several years resealed back in May. At the time they replaced this part, I'll attach the part #. Would I be safe from any oil getting into the harness or do I still need to install some plug or whatever to prevent the oil from seeping into the ECM.H** Replacement of hall sensors

110 ENGINE DIAGNOSIS (GASOLINE)

108911 CEX 91.80 91.80

4 276-905-10-00 POSITION SENSOR

If you already have oil in the connectors, you must replace the upstream damaged component (camshaft position sensor, or solenoid actuator), clean all the oil in the connector with electronic contact cleaner, let it dry. Please move to the ECU and check the connector and clean it as well. Carefully pull/push these connectors, as the tension between the male/female components can wear out, potentially creating a poor contact connection after disturbing the current setup.

The current practice, started by MB in their previous generation engines with VVT, is to use sacrificial harnesses such as
OF COURSE --> PLEASE DISCONNECT THE BATTERIES when working with electricals and spraying connectors.

I don't believe seapage has occurred. I was just asking if the car would be protected for the future as I had the dealer replace it as preventative maintenance, although I don't know if it is the right solution.

Not sure what the dealer is replacing. Fixing the leak from the covers will not prevent future issues, but it will prevent oil from leaking out only through the contact between the metal cover and the engine head. The failures of the camshaft position sensors and/or camshaft solenoid actuators are a separate issue. The only thing in common between those two is OIL.

Changing the non-failed camshaft position sensors or solenoid actuators will not prevent anything either. A new part is not guaranteed to work better than a non-failed part. It is a statistical game about quality control.

I just posted a video on youtube cold starting my 2015 ml350, what do you think, is that a rattle?


If any of you can give input that would be amazing since ill be revisiting my mechanic tomorrow on what to do next for the leaking upper timing covers!

One other thing to note is once before (like 3 or 4 weeks ago) i tried to start the car and the car did not crank then when i took out the key and reinserted it, it started fine. although I had my old battery on at that time (original 10 year battery) when that happened but since then I changed the battery out a few days ago and not had it repeat or anything.

Take a look at this video for the start up rattle. At 1:26 the mechanic provides an example.

that videos startup sounds much different than mine, his sounds like something is knocking in there. Mine in just unusually loud for 30 seconds or so in a cold start and goes away. What do you guys think?

The only sound that I would worry about, IF any, is between the start and the 5-second mark, then it is normal. The rest of the audio is just a M276 engine running normally at cold start. It is warming up to a higher RPM. Recall that it is a direct-injection engine, not a port-injected one and a lot noiser.

THATS EXACTLY MY CONCERN, the start to five second mark concerns me as i feel like something is going on but cant pinpoint it. Have you had this startup on your ml350?

Here is a thread by someone else where I posted two videos for the 2014 E350, and the 2015 ML350 we own. It is buried in the sub-thread (9 replies) with my previous answers.

https://www.facebook.com/share/v/1D3x6E4san/

From what I have seen so far, the photos and the videos, and if this were my ML, I would carefully clean the timing covers with a "brake cleaner" wetted drag/brush, no spray anything, and recheck the area a few days later and see how it progresses. If you decide the oil leak is critical to fix immediately, I would replace the chain tensioners simply because it is an open and straightforward task.
My 2c

My ML sounds the same on startup as well, it does have a pretty noisy engine and nowadays I do hear a lot of ticking sound, but thats just natural from the engine I believe, nothing like the rattle in the video where the camshaft adjusters went bad.

Thats good to hear, i just want to fix whatever this is along with the leak, even if i have to throw 3k at it. once i handle that upper timing cover leak and the loud sound im sure ill be fine for another 80-100k for any timing issues as long as I do 4k-5k oil changes. Whats your miles at and have you added a Camshaft Solenoid Wiring Harness Protection Kit? Im still researching that and you should too as if the oil wicks up the harness into the ecu than it can cause a 10k repair.