Noisy Startup
Thread Starter
Senior Member
Joined: Jun 2008
Posts: 473
Likes: 1
From: Long Island, New York
2019 GLA 250 - I am in purgatory right now...
Noisy Startup
Hey Guys,
I am concerned. I've got 10K on my C300 now and I LOVE it. However, after a good highway run (going to work) If I let the car sit and start it 3 hours after and up to 5 hours after, I get a rattling noise that to me sounds like a crank knock. If you do it any sooner or after that time frame it sounds fine. Cold starts are fine.
It seems to me as if the oil is too thin and when I start it hot it cannot protect the bearings; maybe it's drained from the journals a bit?
Anyway, My dealer said it's carbon build up and not to worry. I know that's a BS answer, but it really ticks me off.
Also, I got an 07 loaner and also made some different, but wired noise on the hot startup.
Is this normal? should I stop worrying? Should I be more concered?
Thanks in advance.
RickP
I am concerned. I've got 10K on my C300 now and I LOVE it. However, after a good highway run (going to work) If I let the car sit and start it 3 hours after and up to 5 hours after, I get a rattling noise that to me sounds like a crank knock. If you do it any sooner or after that time frame it sounds fine. Cold starts are fine.
It seems to me as if the oil is too thin and when I start it hot it cannot protect the bearings; maybe it's drained from the journals a bit?
Anyway, My dealer said it's carbon build up and not to worry. I know that's a BS answer, but it really ticks me off.
Also, I got an 07 loaner and also made some different, but wired noise on the hot startup.
Is this normal? should I stop worrying? Should I be more concered?
Thanks in advance.
RickP
Super Member
Joined: Jul 2002
Posts: 678
Likes: 1
From: Vancouver WA
'14 GLK250 Diesel
I don't know what to say. Ours has 8500 miles, and sounds the same, hot or cold. We just had our service A [coming up on the one-year mark], and new oil made no difference - it always starts and runs instantly and quietly.
"Carbon buildup"? What baloney....
Wish I could hear it personally - talking about engine noises online is always dicey.
"Carbon buildup"? What baloney....
Wish I could hear it personally - talking about engine noises online is always dicey.
MBWorld Fanatic!
Joined: May 2004
Posts: 1,093
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From: California
2014 C250 sport
These engines, especially the 300, have a very high compression ratio, which does make them slightly noisier than normal. Theyre also more prone to knock because of this. But it's hard to tell if the sound you're hearing is normal without hearing it. I know at a cold start the engine sounds kind of "crackly", almost like the cats are bad. But all these new DOHC V6's sound a little noisy, we have three of them.
Thread Starter
Senior Member
Joined: Jun 2008
Posts: 473
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From: Long Island, New York
2019 GLA 250 - I am in purgatory right now...
I wonder if I can post a wave file here? I'll go out at lunch and make a recording. I'm not sure how good it will come out but I'll give it a try. Thanks guys.
RP
RP
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My car has the same engine noise issue. The engine noise is inconsistent from one start-up to another. I could have a smooth and quiet running engine when the car is coasting or when I am accelerate from stop at one moment. The next moment after a start-up (the engine is stopped running for 1/2 hour), I could have an engine that sounds like it has a loose exhaust manifold or a "throaty" sound when the car is coasting or when I am accelerating from stop. Weather temperature dependent??
Weather temperature dependent??
Last edited by johff; Jun 29, 2008 at 02:02 AM.
Senior Member
Joined: Dec 2005
Posts: 371
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From: NJ
ML 350-Black=Sold. New 08 C300 4Matic, Black/Black, P1, Ipod, Auto7speed, 10/10 hit 100,000 miles
Sounds like a common issue, I t also and my BIL said he gets it sometime with his ML350...so, who knows?
Thread Starter
Senior Member
Joined: Jun 2008
Posts: 473
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From: Long Island, New York
2019 GLA 250 - I am in purgatory right now...
I sure hope it is. I was thinking of taking it to an outside mechanic to get an opinion on. But I want to find a mechanic that deals with exotic cars and where if I get something in writing it might carry some weight. I don't mind paying a few bucks for an opinion. Problem is good shops like that don't advertise and I don't know where to find them. Anyone have any ideas?
Rick
Rick
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From: Chesapeake, VA
'08 C300W Lux
I've only got 516 miles on my C300 Luxury's clock & I got consistent cold start knocking from the 1st cold start-up on. When I say cold, I mean anytime the engine has been off 2 hours or more. No performance complaints otherwise but I'm afraid of what kind of response I'll get from my dealer at the 1K-3K service visit. I guess I'd rather learn it's legitimately not a problem as I don't want to think about my engine being torn apart. But better now than 2 years from now.
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Thread Starter
Senior Member
Joined: Jun 2008
Posts: 473
Likes: 1
From: Long Island, New York
2019 GLA 250 - I am in purgatory right now...
Mine is still the same, but with no ill effects. I'm going to take it back to the dealer in a few weeks and just keep logging complaints unless the inevitable happens....
RickP
RickP
Junior Member
Joined: Jul 2008
Posts: 44
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From: Chesapeake, VA
'08 C300W Lux
Talked to my Service Manager today who says hers does the same thing & not to worry. Setting me up for a overnight stay to listen themselves during my 1K-3K diagnostic test visit. Can't believe how severe it is, then it gets silky smooth. Strange!!
MBWorld Fanatic!
Joined: Nov 2008
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From: Dallas
2015 Carrara White Metallic Porsche Cayman
Any solution to this problem?
Mine's been doing it lately. The engine is perfectly smooth while driving but I get the knocking on startup anytime the car has been sitting for more than a few hours.
It's not severe, but it's enough to be embarrassing when I have people with me and I start the car (especially in a garage) and my year old Mercedes sounds like an unrefined truck.
Mine's been doing it lately. The engine is perfectly smooth while driving but I get the knocking on startup anytime the car has been sitting for more than a few hours.
It's not severe, but it's enough to be embarrassing when I have people with me and I start the car (especially in a garage) and my year old Mercedes sounds like an unrefined truck.
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C
Are you guys talking about the knocking sound that lasts a few seconds on a cold startup? My car has that noise. I hear it's related to the fuel pressure although not sure about the exact details
Last edited by Samieee; Sep 19, 2010 at 01:06 PM.
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Joined: Sep 2009
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From: Dix Hills, New York
2012 C250 Coupe
My car does the same thing too. Not all the time, but I have been unable to determine when specifically it does it. To me, it doesn't seem like there is a pattern, but more of a random occurrence.
Also, sometimes when I start my car, occasionally the engine would crank a few more times than normal when I start it, and it almost sounds like I didn't hold the key to the ignition on position long enough to turn it on. Almost like it cranks, stops for a split second (gets silent) and then has a rough startup, but then almost instantly after startup the engine is smooth and perfect. Now that I think about it, this issue is commonly followed by the knocking... Maybe they are related? I will bring it up to my service advisor when I go in 3 days from now. I don't think it is anything serious, but it is a bit embarrassing. I am 90% sure they will just say its normal don't worry about it. lol.
Also, sometimes when I start my car, occasionally the engine would crank a few more times than normal when I start it, and it almost sounds like I didn't hold the key to the ignition on position long enough to turn it on. Almost like it cranks, stops for a split second (gets silent) and then has a rough startup, but then almost instantly after startup the engine is smooth and perfect. Now that I think about it, this issue is commonly followed by the knocking... Maybe they are related? I will bring it up to my service advisor when I go in 3 days from now. I don't think it is anything serious, but it is a bit embarrassing. I am 90% sure they will just say its normal don't worry about it. lol.
Super Member
Joined: Jan 2007
Posts: 846
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From: da long island
1989 Toyota Tercel Coupé
I sure hope it is. I was thinking of taking it to an outside mechanic to get an opinion on. But I want to find a mechanic that deals with exotic cars and where if I get something in writing it might carry some weight. I don't mind paying a few bucks for an opinion. Problem is good shops like that don't advertise and I don't know where to find them. Anyone have any ideas?
Rick
Rick
Take it to the dealer, take it to a different dealer. Let them keep the car for a few hours and tell them to start it back up. You are under warranty, let them figure it out.
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Joined: Oct 2008
Posts: 2,601
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From: Atlanta, GA
2008 C300 Sport 6 Speed Manual, 1953 Chevy Bel-Air, 2015 Audi allroad, 1963 Chevy Apache
I get the same noise on warm starts. Never happens on a fully cold start or a start with less than 1/2 hour....just that in between time. It sounds like the cams, pistons or some other moving piece slapping around a bit. It is not consistant but has been happening more often. I hope it is just oil pressure related and not something that will be wearing down about the same time the warranty gives out.
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Joined: Nov 2007
Posts: 24
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c 300
My car does the same thing too. Not all the time, but I have been unable to determine when specifically it does it. To me, it doesn't seem like there is a pattern, but more of a random occurrence.
Also, sometimes when I start my car, occasionally the engine would crank a few more times than normal when I start it, and it almost sounds like I didn't hold the key to the ignition on position long enough to turn it on. Almost like it cranks, stops for a split second (gets silent) and then has a rough startup, but then almost instantly after startup the engine is smooth and perfect. Now that I think about it, this issue is commonly followed by the knocking... Maybe they are related? I will bring it up to my service advisor when I go in 3 days from now. I don't think it is anything serious, but it is a bit embarrassing. I am 90% sure they will just say its normal don't worry about it. lol.
Also, sometimes when I start my car, occasionally the engine would crank a few more times than normal when I start it, and it almost sounds like I didn't hold the key to the ignition on position long enough to turn it on. Almost like it cranks, stops for a split second (gets silent) and then has a rough startup, but then almost instantly after startup the engine is smooth and perfect. Now that I think about it, this issue is commonly followed by the knocking... Maybe they are related? I will bring it up to my service advisor when I go in 3 days from now. I don't think it is anything serious, but it is a bit embarrassing. I am 90% sure they will just say its normal don't worry about it. lol.
MBWorld Fanatic!
Joined: Feb 2004
Posts: 3,986
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From: SEATTLE WASHINGTON USA
'08 C300 Lux Barolo Red Beige Leather P2 MM 18" wheels '84 944
knock knock knock
It's related to oil pressure buildup and my car started making this little noise at about 1000 miles. And, my 2001 C320 did precisely the same all of time I owned it.
My MB service manager told me that it's common and not harmful. This is NOT a version of "they all do that."
