Noisy engine when first started. Is this normal or is something wrong?
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From: NYC
2012 C300 4Matic
Noisy engine when first started. Is this normal or is something wrong?
When I first start the engine, it sounds alright.
Then after about 10 - 15 seconds when the idle drops down (as it normally does) I start to hear this metallic noise, sounds like the timing chain but I'm not sure. It lasts for maybe 5 - 10 minutes, and then as the engine begins to warm up it's gone. The sound increases with the RPMs if I rev the engine.
The temp outside was 40 degrees and I changed the oil only a few months ago (with the proper 0W40 mobile 1 european formula, w fleece filter). I've noticed this sound since I got the car, but now it sounds a bit louder.
Engine only has ~ 25k on it!
I'm not sure if this is the timing chain or just something on the accessory belt...
I'm going to upload a sound clip as soon as I can. Warranty only has a few months left. I have a feeling my very crappy dealer is going to just tell me its normal regardless.
Then after about 10 - 15 seconds when the idle drops down (as it normally does) I start to hear this metallic noise, sounds like the timing chain but I'm not sure. It lasts for maybe 5 - 10 minutes, and then as the engine begins to warm up it's gone. The sound increases with the RPMs if I rev the engine.
The temp outside was 40 degrees and I changed the oil only a few months ago (with the proper 0W40 mobile 1 european formula, w fleece filter). I've noticed this sound since I got the car, but now it sounds a bit louder.
Engine only has ~ 25k on it!
I'm not sure if this is the timing chain or just something on the accessory belt...
I'm going to upload a sound clip as soon as I can. Warranty only has a few months left. I have a feeling my very crappy dealer is going to just tell me its normal regardless.
Last edited by acr2001; Dec 27, 2008 at 05:43 PM.
Thread Starter
MBWorld Fanatic!
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From: NYC
2012 C300 4Matic
More of a grinding noise but I wouldnt use the word grinding. Definitely not a ticking. The best thing I can compare it to, is the sound a chain makes I don't mean a timing chain but an actual chain. I'm starting to think its something on the accessory belt. I know I could easily determine this by taking the belt off and letting it run for a minute or so, but I have a feeling getting the belt back on isn't going to be so easy.
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Joined: Jul 2008
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05 c230 kompressor
its ur belt and tensioners. i had this replaced by the dealer under the warranty. u hear the problem more during start up. i say go to the dealers if u still waranty and just leave over night. so that the next morning they could hear exactly what ur talking about.
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
If it was the timing chain - and it's common on the 4 cyl engines - not 6. The chain would rattle at initial start up even on high idle & become quiet as soon as the oil pressure came up.(hydraulic tensioners) It certainly would not last 5 to 10 minutes unless something was very wrong. Belt tensioner is likely - presume you are not running the aircon for demisting?
Thread Starter
MBWorld Fanatic!
Joined: Nov 2007
Posts: 2,078
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From: NYC
2012 C300 4Matic
If it was the timing chain - and it's common on the 4 cyl engines - not 6. The chain would rattle at initial start up even on high idle & become quiet as soon as the oil pressure came up.(hydraulic tensioners) It certainly would not last 5 to 10 minutes unless something was very wrong. Belt tensioner is likely - presume you are not running the aircon for demisting?
I also noticed today that when you turn the engine off, the sound continues right up until the belt stops turning (so that's probably around half a second after turning the key off). I'm going to bring it to the dealer before my warranty runs out. I have a feeling they're going to try to brush it off as a normal noise though because it isn't loud, it's about the same volume as the normal engine sound.
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Joined: Jun 2008
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Yep! our aircons have no clutch but when you load them they can make a noise but this is not so here.
Tensioner pulley! - mine makes a high frequency whine but it's been consistent for 47,000 Kms so I don't care.
Tensioner pulley! - mine makes a high frequency whine but it's been consistent for 47,000 Kms so I don't care.
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MBWorld Fanatic!
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From: Sydney, Australia
190D 2.5 (x2), 190E 2.6, W202 C240,W202 C43 (C55), W210 E55, W212 E250CDI
Check that your rear catalytic convertors aren't rattling, it's a fairly common problem that can come and go depending on temperature. Timing chain problems on your engine are ALMOST non-existant. The belt tensioner can be noisy at idle and low revs but rarely when revving.
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Super Moderator
Joined: Jun 2008
Posts: 19,942
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From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Check that your rear catalytic convertors aren't rattling, it's a fairly common problem that can come and go depending on temperature. Timing chain problems on your engine are ALMOST non-existant. The belt tensioner can be noisy at idle and low revs but rarely when revving.
