High pitched squeal from engine
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2010 W212 E350 CGI
High pitched squeal from engine
Hello World! My 2010 W212 E350 CGI starts to make a squealing noise (please hear attached file) once it warms up. I have checked oil and cooling liquid levels and these appear to be fine, and there are no warning messages on my display. Does anybody have an idea what might cause this noise? It could be related to the crank case ventilation valve. Thanks!
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Hello World! My 2010 W212 E350 CGI starts to make a squealing noise (please hear attached file) once it warms up. I have checked oil and cooling liquid levels and these appear to be fine, and there are no warning messages on my display. Does anybody have an idea what might cause this noise? It could be related to the crank case ventilation valve. Thanks!
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
weird whistling....
Hello World! My 2010 W212 E350 CGI starts to make a squealing noise (please hear attached file) once it warms up. I have checked oil and cooling liquid levels and these appear to be fine, and there are no warning messages on my display. Does anybody have an idea what might cause this noise? It could be related to the crank case ventilation valve. Thanks!
Quick PCV test:
Open the oil fill cap to see if the whistling goes away or is affected by pressure changes.
Quick serpentine test:
remove serpentine belt
rotate accessories to find bad bearing(s)
Preventively replace: Tensioner + Idlers + Belt ($100)
Last edited by CaliBenzDriver; Nov 6, 2021 at 11:21 AM.
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Joined: Oct 2010
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
That noise does sound unusual. As you pointed out your PCV could well be at play here...
Quick PCV test:
Open the oil fill cap to see if the whistling goes away or is affected by pressure changes.
Quick serpentine test:
remove serpentine belt
rotate accessories to find bad bearing(s)
Preventively replace: Tensioner + Idlers + Belt ($100)
Quick PCV test:
Open the oil fill cap to see if the whistling goes away or is affected by pressure changes.
Quick serpentine test:
remove serpentine belt
rotate accessories to find bad bearing(s)
Preventively replace: Tensioner + Idlers + Belt ($100)
Please do not do that!! You'll have oil all over the engine bay and then some if you do it. I say this because in my E550 timing chain is right at the oil fill opening. If E350 engine is different then perhaps but I kind of remember my 2011 E350 had the chain at the opening too.
If you want to relieve crank case pressure take the dip stick out.
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From: Pepper Pike Ohio
24 GLS580 '23 E450 4matic 12 E350 4Matic
Sounds like bearing squeal to me,I am from Lugano, but I'm guessing from 2k miles away! As Cali says, quickest way is to pull the serpentine belt and start it, no squeal, its a pulley bearing as Arrie suggests, my 2 cents!
Does the frequency change with RPM's?
Does the frequency change with RPM's?
Last edited by pierrejoliat; Nov 6, 2021 at 01:48 PM.
Out Of Control!!
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
niet...
Open oil fill cap during run!?!
Please do not do that!! You'll have oil all over the engine bay and then some if you do it. I say this because in my E550 timing chain is right at the oil fill opening. If E350 engine is different then perhaps but I kind of remember my 2011 E350 had the chain at the opening too.
If you want to relieve crank case pressure take the dip stick out.
Please do not do that!! You'll have oil all over the engine bay and then some if you do it. I say this because in my E550 timing chain is right at the oil fill opening. If E350 engine is different then perhaps but I kind of remember my 2011 E350 had the chain at the opening too.
If you want to relieve crank case pressure take the dip stick out.
- The dipstick conduit is under oil at the bottom and can hardly vent ANY crankcase air.
- Poping the oil cap for 2 seconds at idle is NOT going to spray any oil all around your engine bay! The nearly dry timing chain spins at less than 400Rpm. . . no big deal.
Furthermore we can readily incorporate Arrie's valuable inputs in these quick tests:
1- try dipstick pop...
2- try oil cap pop!
3- try serpentine accessories
Report findings about noise source. The only thing that maters is not to guess wrong. Even that would be okay as well... serpentine, tensioner, PCV,... are all maintenance items now or repair bill later.
Last edited by CaliBenzDriver; Nov 6, 2021 at 08:31 PM.
MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,143
Likes: 1,297
From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
That's an interesting perspective from a V8 standpoint, I have different notes:
- The dipstick conduit is under oil at the bottom and can hardly vent ANY crankcase air.
- Poping the oil cap for 2 seconds at idle is NOT going to spray any oil all around your engine bay! The nearly dry timing chain spins at less than 400Rpm. . . no big deal.
Furthermore we can readily incorporate Arrie's valuable inputs in these quick tests:
1- try dipstick pop...
2- try oil cap pop!
3- try serpentine accessories
Report findings about noise source. The only thing that maters is not to guess wrong. Even that would be okay as well... serpentine, tensioner, PCV,... are all maintenance items now or repair bill later.
- The dipstick conduit is under oil at the bottom and can hardly vent ANY crankcase air.
- Poping the oil cap for 2 seconds at idle is NOT going to spray any oil all around your engine bay! The nearly dry timing chain spins at less than 400Rpm. . . no big deal.
Furthermore we can readily incorporate Arrie's valuable inputs in these quick tests:
1- try dipstick pop...
2- try oil cap pop!
3- try serpentine accessories
Report findings about noise source. The only thing that maters is not to guess wrong. Even that would be okay as well... serpentine, tensioner, PCV,... are all maintenance items now or repair bill later.
But to the point, I don’t know how many people has checked for this but in my 2013 S550 with the twin turbo engine the dip stick is totally dry while the engine runs. I was very surprised to find this out and had to re-check it several times to believe it so if I want to relieve crank case pressure I just pull the dip stick out.
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Thread Starter
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2010 W212 E350 CGI
Hi CaliBenzDriver, I did remove the oil cap but it did not affect the noise. Some oil did squirt out but it was not too bad. Will check the serpentine belt and pulleys next. Thanks a lot for your valuable tips, will get back to you with an update soon!
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2010 W212 E350 CGI
Hi Pierre, thanks a lot for your input, hope it is warmer in Ticino than here in Zürich . The noise does change with the RPM; when I rev the engine the noise increases in frequency and this persists for a while even if I let go on the throttle. I guess this makes it more likely to be a ball bearing issue? Thanks again!
. The noise does change with the RPM; when I rev the engine the noise increases in frequency and this persists for a while even if I let go on the throttle. I guess this makes it more likely to be a ball bearing issue? Thanks again!
MBWorld Fanatic!
Joined: May 2012
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From: Pepper Pike Ohio
24 GLS580 '23 E450 4matic 12 E350 4Matic
Hi Pierre, thanks a lot for your input, hope it is warmer in Ticino than here in Zürich . The noise does change with the RPM; when I rev the engine the noise increases in frequency and this persists for a while even if I let go on the throttle. I guess this makes it more likely to be a ball bearing issue? Thanks again!
. The noise does change with the RPM; when I rev the engine the noise increases in frequency and this persists for a while even if I let go on the throttle. I guess this makes it more likely to be a ball bearing issue? Thanks again!
