Gents,

Please show some lovely photos on how clean is your engine from oil leak.
I assumed car/engine is old enough by now or you owned it long enough and you have done oil fix leak on it.

If M276.9xx the 3.5L or M276.8xx the 3.0 Turbo and M278 or M157, the usual VVT mini window leak is the common problem and if not kept in check can burn alternator by overheating it thru oil coating it.
If M272, I have no clue where is its highest leak region.

Example of M276 3.5NA typical leak



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M278 typical oil leak, perhaps M157 very similiar



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M272 and M273 typical oil leak location, as per FCP Euro


Thank you.......

 

I had the cam covers and magnets replaced a couple of months ago on my 2016 E350 Sport because of an oil leak on the right side above the alternator. No other leaks were visible anywhere else—no oil intrusion in any of the engine wiring. The alternator was covered with oil, looked somewhat baked on, not wet, but the shop cleaned it up very well, with no problems. A month earlier, I replaced the fuel pump and filter under the back seat. Engine mounts were fine. Mileage is right at 100k.

I asked 2 different shops about my list of possible refresh tasks because of the 100K mileage, and both shops said they wouldn't unless there was some sign of a problem.The car runs perfectly, so I'm going with that.

 

I had the Cam seal replaced when car was at 44K miles. The dripping oil damaged the alternator which was replaced a couple of months later. No other oil leaks and now we're at 58K miles.

 

I had a look this morning... never washed 80kMi. engine fairly dry.

Getting my blow-by pressure under control stopped crankcase pressure relief.


80kMi mixed City + Hwy


up & down California hills
I need 2500.Rpm driveability more than WOT racing

> MB Precision ...
Mercedes has refined the old concept of oil leaks.

• Through the updated CPS into harness.
• Through the PCV onto intake valves.
• Through the timing cover back into crankcase.

We get to deal with internal oil leaks.



(magnets all around filter)
steel shavings collection results very soon


over water pump


Bk1 valve cover front



some old early sticky stuff here...


Bk2 head driver side


ALT like new... ALT-LIN !!



Bosch ECU over Bk2 exhaust 🙏

I wish engine rear was more accessible to see the Bk2 intake cam plastic cap.

As long as blow-by is worked out everything else falls back in place :

• no busy leaks,
• no heat-soak damage,
• no intake swamp,
• no coated valves,
• no burnt coils,
• no inj. filled cylinders,
• no lean misfires,
• .?.

A lot less headaches without stock heat.


Dirty oil leaks are related to dirty valves:
They witness the same root cause.
Normalized blow-by cancels out more than just leaks.

 

Because it was only 400KM ago, albeit 6 month ago I was replacing lots of cooling, engine and tranny oil and HVAC-R134A handling components of my engine, it is now at its superb cleanliness.
I mean all the nook and cranny is accesible back then. I even removed both the turbochargers, so great acccess.




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If all installed, M276.8xx 3.0 Turbo front side is very crowded due to the chargecooler system.
Jakarta ambient dust when car get used on the road is just bad.
NOte : Ignore the left side, Front SAM rather messy, I am still doing Fuse Pulling/Blown simulation.


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It look nice & shiny.

I'm not used to seeing the intercooler between the engine and front radiator.
You do have the benefits of a more effective oil separator unlike NA.

MB turbines bearings seem pretty reliable, right?

 

I took my E550 to a shop right after I got it. In my baseline inspection (the post-purchase inspection for more detailed things that a seller is just going to roll their eyes at), I noticed the front diff was leaking a little. I took it to the shop it had been going to to have them fix that, try out the legendary Carmax warranty, and see what it's like having a shop touch my stuff. They fixed the leak, and said the oil cooler housing was leaking. A few other things I'm sure I'm not remembering. They "fixed" the oil cooler housing leak, but seems they lived up to the reputation of every shop everywhere and did a **** job. I re-resealed a few months ago. Kinda hard to really get it clean with the very minimal clearance the V8 allows (already had the fan out, and still couldn't get a decent chunk of it. Looked around at the time, and that was it. Everywhere else was very nice.

I've had or worked on cars from every make out there from Ford to Ferrari (the Ferrari is my neighbor's, I would never own a Ferrari and the only Ford I'll let near me is my '51 truck bed trailer because it doesn't have a Ford engine in it), and I'm really liking this Mercedes. Very nice to work on, very well made, feels especially solid (best word wife and I have been able to agree on). I rarely keep a car long enough to renew the tags, but this one is about to get a THIRD year's worth of plates! :-0 Not only that, but when my mind does its thing and starts thinking about the "next one", for the first time ever I'm thinking of basically the same thing, just maybe newer. Maybe I'm getting old. Maybe two kids and a startup have sapped my appetite for wrenching. Or maybe it's just a really good car...

Now if I could just figure out wtf is wrong with my suspension!

 

My 2012 276 doesn't have any yet, but I have 33k miles, it has just become the primary driver as I sold my '13, so I will look out for any in the upcoming months

 

My 2016 276 doesn't have any yet either at just barely 50k miles but I'm due for some maintenance and will have the shop take a close look.

 

m272, for an engine close to 240k miles it’s not bad minus the dirty area around the oil filter housing, I have another leak there, this time I’m going to replace the whole housing not just the gaskets. I love cleaning the outside and inside of the car but not a fun of cleaning the engine bay myself, it’s been over 10 years since I had it professionally cleaned.

 

2014 E350 with around 126k miles: zero leaks. No pics, but all looks good and grunge free.

Edward

 

Wow, 2012 with 33K miles or 53K KM, is very much like mine in low mileage term, 2014 being 44,000KM only

 

My engine bay dirtiest moment.........
https://mbworld.org/forums/e-class-w...lant-work.html


Spoiler

This image below is RIGHT SIDE BANK. Alternator is at right side bank, lower side. M
HVAC compressor is at Left Side Bank, lower side.




Engine oil leak will also drip down to Electric Power Steering connector



Alternator location, with alternator REMOVED

My car is RHD, so you can see the steering link on right side bank of the engine.



If my mileage were much higher back then in 2022 ( probaby 36,000KM max ) meaning more oil leak covering the alternator, this alternator might have been cooked , lucky I fix the leak back in 2022.






ALTERNATOR BODY : Between the 2022 oil leak fix fix and Sept 2025 refresh or approx 8,000KM later, the serpentine belt and ambient dust are as below :


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Yes, we had two other cars so this one sat a lot, Maintenance was done by years not miles, this one's never been in the salt or snow as we drove the '13 in the winter

 

Sweet......

 

I wonder how the constant humidity in Jakarta and S.E. Asia affects car's seals and overall longevity. Is it a plus or a minus?

 

High humidity 65% to 95% RH ish all day long and being +5C to 9C ( 30 - 34C ) above typical international room temperature of 25C... kills plastic, rubber and leather sooner
than a nice 20C at say 40% RH. The foams in the car interior, the soft ones, has been turning into dust when squuezed as early as 8th year. These foams usually protects wires from making noise.
The firm foams on seat and for carpet is OK.

Even tires dry rot faster in the tropics, thus I keep my tires life to 4 years max from date of maufacture, or 3.5 years if from date of installation and I buy tires max 6 months old stock usually.
Above 3.5 years tires get noisier and less traction, and dangerous if I do high speed long run to Bali, where there is 200KM of highway which I can do fast enough and long duration enough on Java island.
if traffic is low...at 34C ambient temperature and I do not know the tarmac or concrete surface temperature of the road....surely very hot.


The only tire I wear out properly is the 2nd set, but at the track ... LOL.
1st one Potenza run-flat is original to the car since 2014 and when I bought the car in May 2018 I replaced it immediately ( 4 years tire is too old ) with Michelin Pilot Sport 4, the 2nd set.



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3.5th tire changes are just bad luck and does not count.

By next year 2027 ending, I must replace my Michelin Pilot Sport 5, which now my car mileage only 43,665 KM as per 14th April 2026, even today 17th April still the same.
Max 5,000KM of tire use for now or at best total 10,000KM of use if I ever do Jakarta-Bali run in 2026 or 2027 when these tires get replaced end of 2027.
June 2023 to Dec 2027 = 3.5 years.

I want to try Good Year Eagle F1 Asymetry 6. This one : https://www.tyrereviews.com/Tyre/Goo...ymmetric-6.htm
It is as good if not better than Michelin Pilot Sport 5 and I bought a set for my wife's Toyota Corolla Cross and its not bad and considered quiet for a High Performance Summer Tire.
Original tires for the T-Corolla Cross is the Michelin Primacy 4.

I trust this guy a lot. He knows tires and how to drive hard and is honest.


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The last 4 years since early 2022 have been expensive ..............low mobility on the car, but services do go on of course.
The engine oil in red numbers are the very very low mileage, but months exceeded. My target is maximum 9 months old oil and not 12 months....or approx 5,000 KM or 200 engine hours.


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Engine oil been Mobil 1 OW-40 MB approved version since day 1 of my ownership, unless I wrote other brands like Ravenol or the Liqui Moly which I do not like.

The good thing about tranny oil get replaced so soon and so often, its so smooth and so responsive.
Even DIY, tranny oil + oil filter replacement is the most expensive and troublesome.

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