Knocking Sound 2014 E350 M276
#1
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
Knocking Sound 2014 E350 M276
Recently my 2014 E350 developed a weird knocking sound coming from the rear of the engine, close to the firewall, on the passenger side with no codes or check engine light. There was alway this weird noise coming from that area of the engine for years that I understood was the high pressure fuel pump, but the noise has gotten louder and louder in the past 30 days to the point where it sounded like a Diesel Semi Truck. Could it be a failing pump or piston slap?
This is a video of the issue:
Any ideas what it could be? No check engine lights has been illuminated on the dash yet.
This is a video of the issue:
Any ideas what it could be? No check engine lights has been illuminated on the dash yet.
#2
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2010 E550, 273 Engine: 2012 S550, 278 Engine
Recently my 2014 E350 developed a weird knocking sound coming from the rear of the engine, close to the firewall, on the passenger side with no codes or check engine light. There was alway this weird noise coming from that area of the engine for years that I understood was the high pressure fuel pump, but the noise has gotten louder and louder in the past 30 days to the point where it sounded like a Diesel Semi Truck. Could it be a failing pump or piston slap?
This is a video of the issue: https://www.youtube.com/shorts/6iQa5CqUY7A
Any ideas what it could be? No check engine lights has been illuminated on the dash yet.
This is a video of the issue: https://www.youtube.com/shorts/6iQa5CqUY7A
Any ideas what it could be? No check engine lights has been illuminated on the dash yet.
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MBNUT1 (01-03-2024)
#3
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
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2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
Geep,
If you have a video editor which can show the audio channel, that knock sound would be very visible audio signal spikes.
You need to know your engine RPM first, and then you do a minimum 20 seconds video record.
At the video editor , take 10 seconds of the video timeline and count the audio signal spike numbers.
If the suspect is HP fuel pump, your M276 3.5 NA engine uses 3 lobes camshaft for fuel pump.
So, at 600 idling RPM let say, the signal noise spike would be [ (3 lobes x 600 rpm) / 2 ] / 60 seconds = 15 times per second.
Camshaft speed is 1/2 of crankshaft speed.
If your camera can do 60FPS, its better to catch the signal spike.
However, the way I hear the knock-knock sound from your video simply by ear, it is not fast enough to be a HP fuel pump.
Here is an example : https://mbworld.org/forums/e-class-w...rge-valve.html
If you have a video editor which can show the audio channel, that knock sound would be very visible audio signal spikes.
You need to know your engine RPM first, and then you do a minimum 20 seconds video record.
At the video editor , take 10 seconds of the video timeline and count the audio signal spike numbers.
If the suspect is HP fuel pump, your M276 3.5 NA engine uses 3 lobes camshaft for fuel pump.
So, at 600 idling RPM let say, the signal noise spike would be [ (3 lobes x 600 rpm) / 2 ] / 60 seconds = 15 times per second.
Camshaft speed is 1/2 of crankshaft speed.
If your camera can do 60FPS, its better to catch the signal spike.
However, the way I hear the knock-knock sound from your video simply by ear, it is not fast enough to be a HP fuel pump.
Here is an example : https://mbworld.org/forums/e-class-w...rge-valve.html
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#5
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2020 GLS450 / 2024 Ford Bronco / (former) W212 4-matic 350 sport package
The car is direct injection so you certainly have a high pressure fuel pump. Early VW/Audi 2.0t’s (05-10) had a lobe that ran on the cam for the fuel pump (also direct injection). The lobe would wear out, the cam would wear through it, and send metal shavings into the engine. Lead up symptom was engine power cutting out under load. My thinking is if you’re not experiencing abrupt power drops under moderate acceleration, then it’s probably not a bad fuel pump. These cars are extremely fuel efficient, any reduction in the slightest bit of fuel supply into the engine, and you would notice it clearly.
how many miles do you have on the car? Have you ever had the PCV replaced? It’s back there too and does get clogged up after a while. Costs about $800 via indi mechanic to replace (pain in the a$$ to get to). I did mine around 65k miles, and it made a noticeable difference in the smoothness and noise factor of my engine. I didn’t quite have the knocking thst you do, but I was forming a rhythmic ticking, and did have oil leaks in the cam solenoid seals at around 40k miles.
the engine cover comes off with an upward tug. If you can remove it, it should make it easier to isolate location.
hey, at least it’s not at the front of the engine where the timing chain lives!
how many miles do you have on the car? Have you ever had the PCV replaced? It’s back there too and does get clogged up after a while. Costs about $800 via indi mechanic to replace (pain in the a$$ to get to). I did mine around 65k miles, and it made a noticeable difference in the smoothness and noise factor of my engine. I didn’t quite have the knocking thst you do, but I was forming a rhythmic ticking, and did have oil leaks in the cam solenoid seals at around 40k miles.
the engine cover comes off with an upward tug. If you can remove it, it should make it easier to isolate location.
hey, at least it’s not at the front of the engine where the timing chain lives!
Last edited by nc211; 01-06-2024 at 03:21 AM.
#6
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2010 E550, 273 Engine: 2012 S550, 278 Engine
Seems like it, but I haven't noticed any issues while driving, just this knocking noise that keeps getting louder. I always had a low knocking noise issue years ago when the car was still under warranty, and the techs told me it was how the direct injection fuel pump was supposed to sound. Now it's just getting louder and louder.
When it gets bad enough it will take out your cam shaft. Pump is driven by the lobes in the cam shaft.
#7
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2010 E550, 273 Engine: 2012 S550, 278 Engine
Geep,
If you have a video editor which can show the audio channel, that knock sound would be very visible audio signal spikes.
You need to know your engine RPM first, and then you do a minimum 20 seconds video record.
At the video editor , take 10 seconds of the video timeline and count the audio signal spike numbers.
If the suspect is HP fuel pump, your M276 3.5 NA engine uses 3 lobes camshaft for fuel pump.
So, at 600 idling RPM let say, the signal noise spike would be [ (3 lobes x 600 rpm) / 2 ] / 60 seconds = 15 times per second.
Camshaft speed is 1/2 of crankshaft speed.
If your camera can do 60FPS, its better to catch the signal spike.
However, the way I hear the knock-knock sound from your video simply by ear, it is not fast enough to be a HP fuel pump.
Here is an example : https://mbworld.org/forums/e-class-w...rge-valve.html
If you have a video editor which can show the audio channel, that knock sound would be very visible audio signal spikes.
You need to know your engine RPM first, and then you do a minimum 20 seconds video record.
At the video editor , take 10 seconds of the video timeline and count the audio signal spike numbers.
If the suspect is HP fuel pump, your M276 3.5 NA engine uses 3 lobes camshaft for fuel pump.
So, at 600 idling RPM let say, the signal noise spike would be [ (3 lobes x 600 rpm) / 2 ] / 60 seconds = 15 times per second.
Camshaft speed is 1/2 of crankshaft speed.
If your camera can do 60FPS, its better to catch the signal spike.
However, the way I hear the knock-knock sound from your video simply by ear, it is not fast enough to be a HP fuel pump.
Here is an example : https://mbworld.org/forums/e-class-w...rge-valve.html
That would bring the frequency down to 5/sec that could be close to what you can hear on the video.
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#8
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2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
Very unlikely Arrie, usually the worn out parts would be that roller tappet
https://www.fcpeuro.com/public/asset...r5.?1566855041
Because a single roller does 3x more work than the 3 lobes. The lobes will usually be equally worn on 3 lobes.
The Audi-s old model dumb-azz roller tappet usually worn out VERY fast.
This kind of design :
https://www.fcpeuro.com/public/asset...r5.?1566855041
Because a single roller does 3x more work than the 3 lobes. The lobes will usually be equally worn on 3 lobes.
The Audi-s old model dumb-azz roller tappet usually worn out VERY fast.
This kind of design :
#9
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2010 E550, 273 Engine: 2012 S550, 278 Engine
Very unlikely Arrie, usually the worn out parts would be that roller tappet
https://www.fcpeuro.com/public/asset...r5.?1566855041
Because a single roller does 3x more work than the 3 lobes. The lobes will usually be equally worn on 3 lobes.
The Audi-s old model dumb-azz roller tappet usually worn out VERY fast.
This kind of design : https://www.amazon.ca/Suuonee-Follow.../dp/B083TT4FF8
https://www.fcpeuro.com/public/asset...r5.?1566855041
Because a single roller does 3x more work than the 3 lobes. The lobes will usually be equally worn on 3 lobes.
The Audi-s old model dumb-azz roller tappet usually worn out VERY fast.
This kind of design : https://www.amazon.ca/Suuonee-Follow.../dp/B083TT4FF8
#10
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2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
Yes Arrie, best if OP would do full visual check on HP fuel pump and probably also the PCV oil separator on the exhaust camshaft end.
I am home now in my man cave. So I can do the audio frequency check
Weird frame rate though...but never mind.
.
The frequency belongs to camshaft speed of rotation.
Maybe hydraulic lifter noise ?
I am home now in my man cave. So I can do the audio frequency check
Weird frame rate though...but never mind.
.
The frequency belongs to camshaft speed of rotation.
Maybe hydraulic lifter noise ?
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MPTrader (04-29-2024)
#11
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
Thank you for such an in depth diagnostic S-Prihadi! I will get the oil serviced with liqui moly engine flush then add some liqui moly hydraulic lifter additive and will report back! I'm thinking it might be the lifter. My trusted Mercedes shop did an A service last year with Liqui Moly Ceratec, but they are not open until the 12th due to holidays. Fingers crossed!
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2015-E350-Wagon (01-24-2024)
#12
Jeep
Any luck with the oil change & lifter additive? I have the same exact ‘tap tap’ (thought I was only one on the planet) - 2015 e350 wagon M276 with 59,000 miles. I’m beyond concerned and hoping to identify the root cause and proactively make the repair before conditions worsen. Thank you
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
Any luck with the oil change & lifter additive? I have the same exact ‘tap tap’ (thought I was only one on the planet) - 2015 e350 wagon M276 with 59,000 miles. I’m beyond concerned and hoping to identify the root cause and proactively make the repair before conditions worsen. Thank you
#14
You may not believe this but I hope you do. My mechanic found the same exact root cause but on cylinder 4. The porcelain was cracked thus allowing combustion vapor to escape. Could see brown gasses on the connection boot and base of plug. Wild! $1,200 later (diagnosis and spark plug replacement) were fixed. Crisis adverted - for now…..
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2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
How old/mileage are the spark plugs to be that bad ?
They are genuine or aftermarket ?
I never ever in my life owning a car with spark plugs problem, let alone the ceramic cracking, as I replaced them usually ahead of time because I worry more
of steel based s-plugs seizing in an aluminum cylinder head more than anything else.
They are genuine or aftermarket ?
I never ever in my life owning a car with spark plugs problem, let alone the ceramic cracking, as I replaced them usually ahead of time because I worry more
of steel based s-plugs seizing in an aluminum cylinder head more than anything else.
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
How old/mileage are the spark plugs to be that bad ?
They are genuine or aftermarket ?
I never ever in my life owning a car with spark plugs problem, let alone the ceramic cracking, as I replaced them usually ahead of time because I worry more
of steel based s-plugs seizing in an aluminum cylinder head more than anything else.
They are genuine or aftermarket ?
I never ever in my life owning a car with spark plugs problem, let alone the ceramic cracking, as I replaced them usually ahead of time because I worry more
of steel based s-plugs seizing in an aluminum cylinder head more than anything else.
Last edited by Geep 250GD; 02-16-2024 at 01:53 AM.
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
Wow! I can't believe you had the same failure. I owned many cars in the past and had never even though the spark plug could break like this! My mechanic was out of town for a while and I was just driving my older 250GD. My car had the spark plug fail at exactly the same place on cylinder #3. The ignition coil was still good but filled with the brown soot as in your case as well.
My mechanic was out of town for a while and I took it to the dealership first, they said there was nothing wrong with it and just how direct injection was supposed to sound. Thankfully it was sorted out before real damage occurred.
My mechanic was out of town for a while and I took it to the dealership first, they said there was nothing wrong with it and just how direct injection was supposed to sound. Thankfully it was sorted out before real damage occurred.
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
Wow, my ignition coil looked like that and the spark plug failed at exactly the same point but on cylinder #3! luckily my mechanic was also able to figure it out! Thankfully none of the ceramic shattered for me and went inside the engine. I know the Bosch plugs and Mercedes Branded plugs are all the same, never expected this failure to happen so commonly from them.
Last edited by Geep 250GD; 02-16-2024 at 05:13 PM.
#22
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MY'14 W212 M276 3.5NA @60kMi
HEAT STRESSED
Wow, my ignition coil looked like that and the spark plug failed at exactly the same point but on cylinder #3! luckily my mechanic was also able to figure it out! Thankfully none of the ceramic shattered for me and went inside the engine. I know the Bosch plugs and Mercedes Branded plugs are all the same, never expected this failure to happen so commonly from them.
Could better engine cooling decrease heat failures ?
A better oil selection wouldn't hurt. Increased coolant circulation either.
Last edited by CaliBenzDriver; 02-17-2024 at 04:35 AM.
#23
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2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
LOL! I have an engine for you already installed in my car for that price. Sounds like they don't want you as a customer. What'd you do? Eat all the cookies and donuts in the waiting area?
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2014 Mercedes E350 1991 Mercedes 250GD WOLF 1989 PUCH STEYR 230GE
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