Hello all,

I think this is one of my first posts here. Long time browser, love the forum!

I have a 2013 E550 4matic. Car currently has 135k on it, and I am stage 1 tuned with Eurocharged and I love it. Car runs flawlessly!

Unfortunately, over the last few thousand miles, I've been developing an exhaust manifold leak / tick. Sounds like an 03 Econoliner taking off from a light, and super annoying over the amazing exhaust note.

Is there a way to attempt to remedy this leak without any major servicing? I will be the last owner of this car, I'm not married to some OEM fix or by the books remedy, but looking for your guys' experience working on these cars. I believe you can replace a turbo without an engine drop, so I am hoping we can get to some bolts to try and tighten / find the leak within the manifold.

Any Pointers to how to begin tackling this?

Any sound clips?

I have 0 supporting symptoms of valve train issues, or other cylinder related ticking. We've done borescope, new plugs, coils, shut off injector and still made sound. Stethoscope only hears the pinging when on the back of the exhaust manifold that I can reach, and only on the problem side.

Any way to access the manifold through the wheel well for some potential fixes? I know I probably can't get it out that way.

This was taken about 3 weeks ago when I was sending around for opinions and showing local mechanics with my car etc, it's gotten a little louder since then. Sounds identical to the 03 Econoliner pulling off from the light lmao. Very embarrassing

I basically have the same type of sound coming from my m276, I can't tell if it's something loose like a heat shield or worn out hardware, or an exhaust leak.

in my situation, I have basically ruled out everything aside from an exhaust leak. I don’t have any other symptoms that would indicate a valve or Lifter issue, and the sound doesn’t come from that area anyways. No issues with driving or wide-open throttle.

Can you post a video of what you’re sounds like? If you have a mechanics, stethoscope, try prodding around the exhaust manifold, where the turbo is. I was able to hear the exact same ticking sound when I was touching the manifold, but nowhere else on the block. The injectors had a loud sound as well, but all my injectors sounded exactly the same, and none of them have errors.


short of tearing down the motor, I’ve done absolutely everything to rule out valvetrain issues

It sounds normal to me. Check the heatshields.

I’ll check but…There’s no way it can be a heat shield, it taps at half the rpm Consistently and gets louder when accelerating, extremely noticeable, harder to hear over 2k or so due to the speed. Happens hot or cold.


here’s a shot from the back.

just from the videos i would say something engine. exhaust leaks from what iv seen don't sound metallic.

maybe chain tensioners?

Sorry I can't help, but this is funny

car has new chain, tensioners, checkvalves, ALL new coolant lines, new rad, new accessories, new belts, new plugs, new coils, been borescoped, no tapping coming from anywhere on the top / mid end I can find with the stethoscope, and far too tinny to be low end knock. It’s a ticking and pinging - and after comparing to about 400 videos online of various different issues (lifter, valves, etc) the closest sound is an exhaust tick - and I don’t have any other supporting issues- no low compression on that bank, no misfires, wide open throttle is flawless, no engine lights whatsoever.

I have Xentry and have ram it through a gauntlet of tests (cam adjusters, injectors, smooth running, etc).

2 Merc only shops cannot find what it is - but they don’t seem to think it’s anything serious. Without pulling the engine (per my warranty request) there’s no way to really know. And I’d be on the hook for the labor potentially so not worth it if it runs great.

It’s got all the characteristics of an exhaust manifold leak - and they are known to occasionally have issues on these. We’re in the rust belt, so could make sense

new tensioners? well then. i guess it could be an exhaust leak similar to the ford f150. the manifolds get a crack, or the gasket fails and itll sound similar.

I can't tell what noise you're referring to by the vids, and to me it sounds the same on both sides. Is it that faint sheet metal like sound? If so, it seems to come from both sides? Maybe set the phone by the car and take off like you said from a light. Or heck, duct tape the phone to the fender or the the center of the wheel so we get an entertaining video as well :p but something so we can really hear it.
If it is that faint sheet metal sound I'd go with heat shield like the others suggested. I've seen lots of cars where some rando heat shield decides to start rattling and it is very annoying. Generally you can just push on it by hand or with a stick and it'll shut up, so you know that's the source of the problem. Then bending it a bit will usually quiet it, or bend it a lot if difficult. Or just remove or replace it but that's usually too much work.

If an exhaust leak, and I know it's tight as ***** in there, I've used a little piece of tissue on the end of a stick or wire to locate exhaust leaks. Of course you need to also be able to see the tissue flutter which may be just short of impossible in some areas. Another, which you may not like, is to pump some tranny fluid into the intake so it smokes, and that smoke will come out any hole in the exhaust. At the very least you'll see some smoke on the side of the eng and know that yes, there is a leak. If not tranny fluid then I suppose a cleaner like SeaFoam or something similar that smokes.
Back to sheet metal, it doesn't necessarily need to be a heat shield, it can be lots of things including the body of the car. Some rando part could be loose or cracked and make noise simply from the vibration of the engine. I see some motor mounts have a dome like shield, which I imagine could crack or something. I suppose I would use a hose and douche everything in the general area with lots of water to see if that dampens the sound. If you locate it, then a little oil on the exact spot should quiet it.
Keep us updated, for our curiosity and for others in the future that have this issue And any better audio would be nice because it sounds more or less normal to me. Maybe my speakers are not so good at that freq, who knows.

You have done extensive diagnosis. Pinging is a term used to describe non-nominal combustion, is this what you mean?

It seems like you want a poster to agree with you that it’s the exhaust manifold.

I think it’s equally likely to be a sticking valve.

What is your next step? De-mount the exhaust manifold and re-mount it? Or do a deep dive session with WIS to evaluate cam angles in operation?

Did you report on presence of oil, or not, in the cam sensors and cam magnets electrical connectors?

Get someone/shop with these 2 kinds of pressure transducers and a picoscope 4 channels.

01. In cylinder pressure transducer, absolute like a pico WPS500
02. Delta /PulseTransducer

Delta/Pulse Transducer. Can be used at inlet manifold or exhaust system







Pico absolute pressure transducer WPS500 or its equivalent





Very minute leak can be seen with these sensors and someone who is good with these sensors.
For misfire to be registered as DTC, our azz & ear dyno can already sense it well before DTC.

Good luck

If you have not tried smoke test using real smoke machine capable of some pressure, that can be a good way to check in indeed the exhaust manifold has very small leak/s.

========

I used a video editor to count the click/tick sound and it seems this is a valve train region, based on the counts per minute. Does not mean it has to be mechanical sound from camshaft and the gang.




Camshaft rotates half the speed of the crankshaft, that is why I suspect valve train region because 300 ish click/tick per minute is not crankshaft RPM speed.

If say the tick/click sound is a very small leaking exhaust manifold which would also have the same pulse per cylinder, which is 1/2 of engine RPM,
It would likely be at close to the exhaust port ( I marked 1 in blue ) of the engine block where the exhaust pulse is not yet too effected by other 3 cylinders.

If the super minute leak is at the location I mark 2 in blue, it would likely already be at a mixed exhaust pulses region from 4 cylinders and may not sound so distinctive and so low pulse count.





This is 4x slowed down video of your night video. 3 seconds of it where the tick/click sound is obvious.



Hope u find the culprit..........

Hello, did you find if?
W221 M278 engine same ticking noise
158 000kms

Found this thread because I have the same symptom, ticking sound that sounds like an exhaust manifold leak.

If you check my profile, I’ve done extensive diagnostics to try and pinpoint the issue.

I ended up buying a smoke machine and posted a video of the results.

Smoke billows from where the exhaust manifold bolts to the block.

I’m going to try and replace the manifold seal, maybe the entire manifold.

Found this thread trying to research how difficult a manifold replacement is.

What kind of smoke machine? I have the M272 engine and im hearing a loud ticking sound on the passenger side of the engine when driving, up close under the hood at idle it sounds like loud puffs of air, reminds me of a moped I used to have as a kid. Or if you try and start a lawn mower without the spark plug in it, that air sound.

I stuck my phone down in there looking to see if the manifold is damaged and I noticed some staining where the manifold mounts to the engine. Im thinking the gasket is blown out at that location. I bought a replacement manifold since mine looks rusted. I just want to confirm it really is coming from the manifold before i start the project, im not looking forward to it.

Yep looks like exhaust leak to me.

When you get your stuff make sure the studs are also supplied (not sure how MB does stuff), start soaking the exhaust manifold with penetrator whenever the cars gonna be idle for a while. Anything to help get those loose when ya do the job without snapping them off.

If you Google "smoke leak tester", one of those.

Yes that's exactly what mine sounds like, a moped without an exhaust or lawnmower without a plug.
Differences, I have the M273 and don't hear the sound at idle, only under acceleration.

That looks right; I haven't taken photos but definitely should.
Yeah it sounds like an absolutely horrific job. I wouldn't even know how to remove those rusted bolts/studs.
Smoke machine is under $100.
Let us know how it goes. I'm going to have a professional do it because of the potential for having to replace engine studs or whatever those bolts are that bolt the manifold to the engine.

I was playing around and used a shop vac to confirm the exhaust leak at the manifold. I stuck the vacuum hose in one of the exhaust tips and sealed the other one with a towel. Turned the vacuum on and could clearly hear the air being sucked in at the manifold from that corner. The other side was silent.

The local MB dealer has all the hardware I need for around $75. I'm going to see how much the dealer will charge me to replace everything if I supply all the parts. The thought of breaking a stud does have me worried especially working from jack stands.

Yup that looks like it'll do it!

We're on the same page.

From what I've seen, it does NOT look like a fun repair.

Please let us know what you're quoted.

Alright I'm going to make a separate thread, but I've done the research on this job.

I managed to get a WD40 bottle with the straw to hit all of the top bolts of the passenger side manifold.

The bottom bolts, however, I can only reach the front most.

Matter of fact, the ones in the middle (bottom) don't seem accessible at all without removing the engine mount first.

Anyone with M273 experience is needed!!!

I stopped in my local MB dealer to pick up some parts so I inquired how much they would charge me just in labor to replace one exhaust manifold gasket. I was expecting it to be simple to get a price quote, maybe they type in there computer what car it is and the work needed and it spits out the time in hours to do it. Nope, and of coarse I get the person who just started there 2 days ago so he really had no idea. I had the gasket in my hand and just said how much to install this?

After waiting around in the end I was told "ballpark estimate" 5-6hrs at $205/hr, not accounting for any broken bolts that may have to be drilled out.