Strange Noise From Muffler on Cold Start
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From: FairFax, Virginia
Strange Noise From Muffler on Cold Start
I apologise up front - I think the following question has been discussed once before. BUT.... 
My C230K (3 week old with 900+ miles on the Odo) makes weird noise on cold start and the noise lasts for about 30 seconds. It sounds as if an old Harley's warming up in your bedroom. Nearly as noisy just as bad. It sounds troubling - I thought I might have a hole in the muffler.
Is it the the noise/sound we referred to in other posts?
ALso what is the optimal RPM or MPH points for shifting to a higher gear when engaging the touch shifter?
Thank you All.
Peace
My C230K (3 week old with 900+ miles on the Odo) makes weird noise on cold start and the noise lasts for about 30 seconds. It sounds as if an old Harley's warming up in your bedroom. Nearly as noisy just as bad. It sounds troubling - I thought I might have a hole in the muffler.
Is it the the noise/sound we referred to in other posts?
ALso what is the optimal RPM or MPH points for shifting to a higher gear when engaging the touch shifter?
Thank you All.
Peace
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Joined: Jun 2002
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1. don't worry about the noise
2. If you have auto transmission, you don't need to be concerned when to shift ( in manual mode ).. even if you manually shift, the computer won't let you do anything without it's permission
2. If you have auto transmission, you don't need to be concerned when to shift ( in manual mode ).. even if you manually shift, the computer won't let you do anything without it's permission
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From: Mid-Ohio
C230
Re: Strange Noise From Muffler on Cold Start
Originally posted by Benzer
My C230K (3 week old with 900+ miles on the Odo) makes weird noise on cold start and the noise lasts for about 30 seconds. ... Is it the the noise/sound we referred to in other posts?
My C230K (3 week old with 900+ miles on the Odo) makes weird noise on cold start and the noise lasts for about 30 seconds. ... Is it the the noise/sound we referred to in other posts?
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From: Encino
2002 C230K
for shifting it depends on your personal comfort level and how you're driving. the only catch is that at half throttle, it'll be another 400rpm before the car shifts after you nudge the stick. at full throttle, it can be longer.
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From: LA Area
2002 C230K Sports Coupe
Re: Strange Noise From Muffler on Cold Start
Originally posted by Benzer
It sounds as if an old Harley's warming up in your bedroom.
It sounds as if an old Harley's warming up in your bedroom.
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From: Mercedesland
This has been discussed several times before and everybody keeps telling that it comes from the S/C, but I don´t believe it. Firstly, what could make that noise inside the S/C? Secondly, the engines without supercharger makes exactly the same noise.
My guess is that the exhaust valves are kept open longer on cold starts to warm up the cat. Is this a resonable assumption or does anyone have a better explanation?
My guess is that the exhaust valves are kept open longer on cold starts to warm up the cat. Is this a resonable assumption or does anyone have a better explanation?
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From: Nashua, NH
2008 VW GTI
My guess is that the exhaust valves are kept open longer on cold starts to warm up the cat. Is this a resonable assumption or does anyone have a better explanation?
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From: Mercedesland
Originally posted by benzy230
with MY experience...yes..it has been my S/C..as when i changed exhaust the sound went away...and then when i put a 3 inch exhaust straight back....it was worse....
with MY experience...yes..it has been my S/C..as when i changed exhaust the sound went away...and then when i put a 3 inch exhaust straight back....it was worse....
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yes.....somewhat....it was a little more muffle'd than anything...if you listened close enough you could hear it....but not like it was....
its hard to get the sound gone (in which if you do...it kills performance) due to the S/C
its hard to get the sound gone (in which if you do...it kills performance) due to the S/C
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From: Encino
2002 C230K
it's not the s/c, the sound for the first 30s to 1min is from the air pump. it runs until the cat is warm enough in order to keep emissions down. you could probably turn it off, you just wouldnt have as pleasant a scent in the mornings, and you might not pass smog check with it off.
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Originally posted by dswildfire
it's not the s/c, the sound for the first 30s to 1min is from the air pump. it runs until the cat is warm enough in order to keep emissions down. you could probably turn it off, you just wouldnt have as pleasant a scent in the mornings, and you might not pass smog check with it off.
it's not the s/c, the sound for the first 30s to 1min is from the air pump. it runs until the cat is warm enough in order to keep emissions down. you could probably turn it off, you just wouldnt have as pleasant a scent in the mornings, and you might not pass smog check with it off.
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Originally posted by dswildfire
it's not the s/c, the sound for the first 30s to 1min is from the air pump. it runs until the cat is warm enough in order to keep emissions down. you could probably turn it off, you just wouldnt have as pleasant a scent in the mornings, and you might not pass smog check with it off.
it's not the s/c, the sound for the first 30s to 1min is from the air pump. it runs until the cat is warm enough in order to keep emissions down. you could probably turn it off, you just wouldnt have as pleasant a scent in the mornings, and you might not pass smog check with it off.
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From: Ashburn, VA
'19 GLC 300, '19 TM3SR+
Originally posted by dswildfire
it's not the s/c, the sound for the first 30s to 1min is from the air pump. it runs until the cat is warm enough in order to keep emissions down. you could probably turn it off, you just wouldnt have as pleasant a scent in the mornings, and you might not pass smog check with it off.
it's not the s/c, the sound for the first 30s to 1min is from the air pump. it runs until the cat is warm enough in order to keep emissions down. you could probably turn it off, you just wouldnt have as pleasant a scent in the mornings, and you might not pass smog check with it off.
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From: Mercedesland
Originally posted by vadim
benzy230 is right, it IS the supercharger that is used to supply more air to the catalytic converter at startup to heat it up faster. In other cars the same effect is achieved by using air pumps. MB engineers decided to save some cost and weight by using the air pump that's already there - the supercharger. The price - this signature John Deere sound that we have to enjoy every morinig. Electric air pumps are much, much quieter...
benzy230 is right, it IS the supercharger that is used to supply more air to the catalytic converter at startup to heat it up faster. In other cars the same effect is achieved by using air pumps. MB engineers decided to save some cost and weight by using the air pump that's already there - the supercharger. The price - this signature John Deere sound that we have to enjoy every morinig. Electric air pumps are much, much quieter...
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From: Nashua, NH
2008 VW GTI
...and hows does the air get from the s/c to the cat.? Is there a valve & tube bypass assembly? Or does the ECU tell the exhaust valves to stay open longer as someone posted above?
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I kinda like that John Deere sound...
I am the only one who makes fun of it (of my friends and family), but I like it. All the better if it is heating up the cat faster and reducing harmful emissions.
In either case, I am certainly not ashamed of it. But hey, I think I had different motivations for buying mine that some other folks here.
In either case, I am certainly not ashamed of it. But hey, I think I had different motivations for buying mine that some other folks here.
