M276 2012 E350 coupe startup rattle
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Joined: Jul 2018
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
M276 2012 E350 coupe startup rattle
I’m having a startup rattle. It is exactly like this.
not even a difference there. That is the exact sound, and goes away after the same amount of time. Just replaced the chain tensioners. Same sound. What do you guys think? Check valve? Camshaft adjuster?
not even a difference there. That is the exact sound, and goes away after the same amount of time. Just replaced the chain tensioners. Same sound. What do you guys think? Check valve? Camshaft adjuster?
Junior Member
Joined: May 2016
Posts: 43
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From: Boston
2013 E550 Coupe
I had the same sound on cold startup in my M278 at 30k miles. I knew it was the timing chain from experience and use of my stethoscope on the front timing cover. I then insisted the dealer check it out.
They originally said it was normal operating sounds of direct injection. Then blamed the wastegates on the turbos.
They ultimately replaced the tensioner assembly and added a check valve to reduce drain-back and that fixed the problem.
You cant tell them what the problem is though. They have to discover it on their own I guess.
I did learn something from the whole ordeal... I saw on the invoice something i never heard of before, They replaced things called "Hexolobular" bolts. Or TORX head bolts as to you and I
They originally said it was normal operating sounds of direct injection. Then blamed the wastegates on the turbos.
They ultimately replaced the tensioner assembly and added a check valve to reduce drain-back and that fixed the problem.
You cant tell them what the problem is though. They have to discover it on their own I guess.
I did learn something from the whole ordeal... I saw on the invoice something i never heard of before, They replaced things called "Hexolobular" bolts. Or TORX head bolts as to you and I
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Joined: Jul 2018
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
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E550 Coupe 2wd (2016)
On other cars when I hear a similar noise I don't suspect the engine, but metal. Like something hitting heat shielding, like the exhaust. When the eng starts it spins up above normal idle, then settles back down in rpm but the fuel is mix is not right so it shudders causing things to touch that don't normally touch. So I'd start it with the hood open and be ready to locate it. If that's the case I then bend whatever so it doesn't do it anymore. Not saying it's not the chain, but that's awfully loud for a chain and classic for heat shield to exhaust.
Optionally, new motor mounts may cure it too since apparently Benz mounts fail sooner than regular mounts, and loose mounts allow more eng movement to cause probs like that.
My chain makes a wee little noise in comparo, like <1% of yours, and it sounds like you'd expect a chain to sound. It was buggin me so I put in 32oz of Lucas Oil which quieted it way down. Quieted the motor as whole down too
I have no idea if mine has the tensioner mods or not (chart says mine is the same as yours).
Please post with details after you dig in deeper b/c I'm really curious...
Optionally, new motor mounts may cure it too since apparently Benz mounts fail sooner than regular mounts, and loose mounts allow more eng movement to cause probs like that.
My chain makes a wee little noise in comparo, like <1% of yours, and it sounds like you'd expect a chain to sound. It was buggin me so I put in 32oz of Lucas Oil which quieted it way down. Quieted the motor as whole down too
I have no idea if mine has the tensioner mods or not (chart says mine is the same as yours).
Please post with details after you dig in deeper b/c I'm really curious...
Thread Starter
Member
Joined: Jul 2018
Posts: 115
Likes: 13
2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
On other cars when I hear a similar noise I don't suspect the engine, but metal. Like something hitting heat shielding, like the exhaust. When the eng starts it spins up above normal idle, then settles back down in rpm but the fuel is mix is not right so it shudders causing things to touch that don't normally touch. So I'd start it with the hood open and be ready to locate it. If that's the case I then bend whatever so it doesn't do it anymore. Not saying it's not the chain, but that's awfully loud for a chain and classic for heat shield to exhaust.
Optionally, new motor mounts may cure it too since apparently Benz mounts fail sooner than regular mounts, and loose mounts allow more eng movement to cause probs like that.
My chain makes a wee little noise in comparo, like <1% of yours, and it sounds like you'd expect a chain to sound. It was buggin me so I put in 32oz of Lucas Oil which quieted it way down. Quieted the motor as whole down too
I have no idea if mine has the tensioner mods or not (chart says mine is the same as yours).
Please post with details after you dig in deeper b/c I'm really curious...
Optionally, new motor mounts may cure it too since apparently Benz mounts fail sooner than regular mounts, and loose mounts allow more eng movement to cause probs like that.
My chain makes a wee little noise in comparo, like <1% of yours, and it sounds like you'd expect a chain to sound. It was buggin me so I put in 32oz of Lucas Oil which quieted it way down. Quieted the motor as whole down too
I have no idea if mine has the tensioner mods or not (chart says mine is the same as yours).
Please post with details after you dig in deeper b/c I'm really curious...
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Super Member
Joined: Aug 2004
Posts: 954
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E550 Coupe 2wd (2016)
I'm baffled at how the cam adjuster dealie could make that sound. I mean that's a lot of noise for something muffled by all that aluminum, so the actual noise would have to be insane. I can't picture an internal part making that much noise and still work..
If it were bad, and making said noise, would it not continue to make the noise at idle? Why would it be quiet at first, make noise for a couple seconds, then go quiet again until restarted?
I'm not saying it isn't b/c I don't know, but I'm still betting it's the motor shaking. I'm on the edge of my seat either way... If it is this cam thingie I'd love to see pix of it, and your thoughts, so I can wrap my head around the how & why.
Best of luck!
If it were bad, and making said noise, would it not continue to make the noise at idle? Why would it be quiet at first, make noise for a couple seconds, then go quiet again until restarted?
I'm not saying it isn't b/c I don't know, but I'm still betting it's the motor shaking. I'm on the edge of my seat either way... If it is this cam thingie I'd love to see pix of it, and your thoughts, so I can wrap my head around the how & why.
Best of luck!
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Thread Starter
Member
Joined: Jul 2018
Posts: 115
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
I'm baffled at how the cam adjuster dealie could make that sound. I mean that's a lot of noise for something muffled by all that aluminum, so the actual noise would have to be insane. I can't picture an internal part making that much noise and still work..
If it were bad, and making said noise, would it not continue to make the noise at idle? Why would it be quiet at first, make noise for a couple seconds, then go quiet again until restarted?
I'm not saying it isn't b/c I don't know, but I'm still betting it's the motor shaking. I'm on the edge of my seat either way... If it is this cam thingie I'd love to see pix of it, and your thoughts, so I can wrap my head around the how & why.
Best of luck!
If it were bad, and making said noise, would it not continue to make the noise at idle? Why would it be quiet at first, make noise for a couple seconds, then go quiet again until restarted?
I'm not saying it isn't b/c I don't know, but I'm still betting it's the motor shaking. I'm on the edge of my seat either way... If it is this cam thingie I'd love to see pix of it, and your thoughts, so I can wrap my head around the how & why.
Best of luck!
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Joined: Jul 2018
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
Hi all. Wanting to get this thread started again.
I havent yet begun my repairs on the car, but I’m trying something tomorrow.
Ive read that another cause is the camshaft position sensor, which is what I have a code for. It contains the plunger and the magnet.
So tomorrow I’m going to take out the sensor and replace it with the one from my 2014 C300. The part numbers are identical.
Has anyone else encounter and fixed this issue?
I havent yet begun my repairs on the car, but I’m trying something tomorrow.
Ive read that another cause is the camshaft position sensor, which is what I have a code for. It contains the plunger and the magnet.
So tomorrow I’m going to take out the sensor and replace it with the one from my 2014 C300. The part numbers are identical.
Has anyone else encounter and fixed this issue?
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c300
on M276 engine, it's the chain tension that causes the rattling because of low oil pressure before the standard oil pressure can be built. remedy is to plant an oil check valve into oil input hole and have the tensioner replaced.
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
Don’t believe this is correct. i switched the position sensors for the camshaft adjuster and it throws the same camshaft adjuster code. This car has already had tensioners and check valves replaced. So this is definitely a camshaft adjuster. I’ve seen multiple people say the camshaft adjuster is bad. I bought the tools to lock the camshaft in place to see which one is bad.
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c300
Don’t believe this is correct. i switched the position sensors for the camshaft adjuster and it throws the same camshaft adjuster code. This car has already had tensioners and check valves replaced. So this is definitely a camshaft adjuster. I’ve seen multiple people say the camshaft adjuster is bad. I bought the tools to lock the camshaft in place to see which one is bad.
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c300
i begin to agree with you, it's b/c of the camshaft. i opened up the cam cover last week, removed the tensioner only to find out that my engine already has a check valve in the hole. So I just replace a new tensioner. First start is perfect, no rattling. then it came back as it was.
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
i begin to agree with you, it's b/c of the camshaft. i opened up the cam cover last week, removed the tensioner only to find out that my engine already has a check valve in the hole. So I just replace a new tensioner. First start is perfect, no rattling. then it came back as it was.
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Joined: Sep 2019
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2012 ML350
Yep. Camshaft adjuster is the cause. This is an extremely common problem. I’ve replaced the check valves and tensioners as well. I switched the sensors and the code remained the same, meaning that the code is correct for a camshaft adjuster, and not a failing sensor.
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
Have you fixed this yet? I have the same rattling sound on warm start up. Extended warranty fixed the chain tensioner and check valve but the noise is still there. Now check engine light turns on for a bit then turns off. I was able to read a P0346 from my scanner. Shop says to change the camshaft adjuster but warranty will not cover it due to timing is not off. I have been following your posts to see if you got it fixed.
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2012 ML350
I have not yet fixed it but I plan on doing it soon. First I want you to know, is that it will not damage your engine. My car has been doing it for over a year. I had the chain tensioner and check valve replaced as well with no change. P0346 is what I have as well. That is the camshaft position sensor. I switched the sensor to see if it was possibly a bad sensor, and the code still persisted for the same engine bank, telling me that the sensor is correct in detecting an issue on that side of the bank. Mercedes will charge you thousands to do this job. I recommend buying the adjuster yourself and having a shop install it for a total of 6-7 hundred. You will need to buy a kit that locks the camshaft down in order to tell which adjuster is bad. You could do it yourself, the only issue is keeping the car completely stable so you don't throw the timing off and send a rod through your engine block.
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2013 E550 Coupe Designo Edition, 2012 E350 Coupe, 2014 C63, 2018 GLC 300
Thanks for the update. Yeah MB dealer asked 4 grand to fix it. I'll start shopping around for indy shops who will do it. I have 130K miles on the engine thou. Just bought this ML350 and didnt notice this rattling sound since it sounds starts fine during cold and hot start up. Only when the engine is warm after it rested for 20-30 minutes.
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From: Chicago
996TT | ETreeFiddy | URS6
Jumping into this thread as I am about to take this journey. 2013 E350 w just a tick over 80K on it. Car has always had the faint cold start rattle. Threw a code for Bank A/Cam 1 just after some longer start times noticed.
Symptoms progressed after the initial CEL:
For those of you that are afraid to tackle this, it's almost as easy as changing your oil. I didn't even fully remove the intake when I changed sensors (I also didn't remove the covers) and it took me less than an hour start to finish. Once the tensioners and related parts arrive, I fully remove the intake to access the covers but that shouldn't add much more than 30 minutes to the entire process.
My big question here is does anyone have a copy of the timing set procedure if I need to do the chain because of stretch?
Thanks!
*WHOOPS! Wrong forum guys.*
Symptoms progressed after the initial CEL:
- Hard start, but started everytime (About 10X short <5 mile errands).
- Last warm start emitted a louder than normal 'chain-slap' sound that cleared in seconds.
- Driving home (less than 3 minutes) the car started misfiring but no other sounds to note.
- Changed out the sensors noted with the CEL, cleared CEL car ran flawlessly for about 10min. Once at operating temps, the misfire and chain slap returned along with another CEL for the same code.
For those of you that are afraid to tackle this, it's almost as easy as changing your oil. I didn't even fully remove the intake when I changed sensors (I also didn't remove the covers) and it took me less than an hour start to finish. Once the tensioners and related parts arrive, I fully remove the intake to access the covers but that shouldn't add much more than 30 minutes to the entire process.
My big question here is does anyone have a copy of the timing set procedure if I need to do the chain because of stretch?
Thanks!
*WHOOPS! Wrong forum guys.*
Last edited by Ubercarfan; Dec 9, 2019 at 01:02 PM. Reason: Wrong Forum
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c300
sound definitely not motor shaking, because of the frequency and metallic feature, it is the timing, I cannot imagine how the timing make this sound (maybe timing chain slapping the block wall due to excessive slag?)
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Posts: 35
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From: Chicago
996TT | ETreeFiddy | URS6
It's definitely not because of the motor shaking. It's definitely a chain slap coming from the bank 1. I'm pretty certain the tensioner has failed and allows chain slack. I'll update once I pull it apart.
The part number for the cover bolts is: N 000 000 006 365
They are M6 X 16 with 16 total for both banks needed. I am a 276.952 engine.
The part number for the cover bolts is: N 000 000 006 365
They are M6 X 16 with 16 total for both banks needed. I am a 276.952 engine.
Last edited by Ubercarfan; Dec 9, 2019 at 01:57 PM. Reason: Engine No Included
