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Discussion Starter #1
2014 cla45 69,000km odo
When hot, engine makes chirping noise randomly. Benz inspected and said it was from the crankshaft ventilation system. It has a problem whereby the pressure is finding a different path to release. Said shouldn’t be reliability issue but big job if to be rectified. Anybody else heard of someone like this?
Thanks in advance
 

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So they think the pcv valve is dying?
as in positive crankcase ventilation
wow ... so if its venting through somewhere or something else that aint good
can you / they localize the sound source??
 

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2014 cla45 69,000km odo
When hot, engine makes chirping noise randomly. Benz inspected and said it was from the crankshaft ventilation system. It has a problem whereby the pressure is finding a different path to release. Said shouldn’t be reliability issue but big job if to be rectified. Anybody else heard of someone like this?
Thanks in advance
This is due to having to much oil in the system at some point and it gummed up the crank vent. I had the same issue and yes it is a big job. The pressure is pushing the crank seal up against the pulley and that is what makes the chirping noise. Try removing the oil cap while running and see if the noise disappears. He is a link to mine before the fix.




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Gosh this too much oil thing is getting out of hand
Gotta read the lines on the stick!
I keep mine between 9 and 13 ticks (with 2 full turns before reading) and so far so good
 

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Discussion Starter #5
This is due to having to much oil in the system at some point and it gummed up the crank vent. I had the same issue and yes it is a big job. The pressure is pushing the crank seal up against the pulley and that is what makes the chirping noise. Try removing the oil cap while running and see if the noise disappears. He is a link to mine before the fix.




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Yep that’s the exact noise. What fix was applied? Any other things to mitigate? Cheers!
 

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Yep that’s the exact noise. What fix was applied? Any other things to mitigate? Cheers!
They first tried taking out the excess oil and the noise was still there. Then changed the belt. To fix it They had to change out the crankcase vent line which is pretty extensive. I also had oil leaking out of the air intake tube at the turbo inlet so they replaced that too. I was under warranty and the dealership was the only ones that worked on it and they overfilled the oil. I do my oil changes now and fill it half way between the full and low mark.


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Gosh this too much oil thing is getting out of hand
Gotta read the lines on the stick!
I keep mine between 9 and 13 ticks (with 2 full turns before reading) and so far so good
2 full turns?


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2 full turns?
Yup
Push that yellow thingie all the way down
Rotate at least 2 full turns
Then extract ... much easier to read else its lopsided and dont know which mark is which
I usually extract / clean / read 3x just to be sure
Just checked mine today and its holding steady ay 13 ticks (56% level) after recent oil change #6 on 2/9
 

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Yup
Push that yellow thingie all the way down
Rotate at least 2 full turns
Then extract ... much easier to read else its lopsided and dont know which mark is which
I usually extract / clean / read 3x just to be sure
Just checked mine today and its holding steady ay 13 ticks (56% level) after recent oil change #6 on 2/9
Makes sense. I never did think to do that due to it being lopsided. Thanks!


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Discussion Starter #10
Thanks guys

Merc said reliability wise it shouldn’t be an issue, what do you think?
Getting a quote for the work just in case
 

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What? The pcv system has been messed up due to oil overfill and theres no long term concerns?
Really?
If they are so confident ... maybe consider getting it in writing with a complimentary repair clause if an associated failure occurs
 

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Discussion Starter #14
So hit up merc and they have sent the quote for the work...$4.2k aud

I thought it had been overfilled last service but oil level seems ok as per above pic. Hadn’t noticed noise prior to the service, could of been overfilled prior to ownership.

Merc said over filling is one cause but did not mention others. Probably going ahead with repair (sighs), thanks for insights guys.
 
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