johff

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 sounds "gruffy" when the car is coasting or when I am accelerating from stop.

The "gruffy" sounds is very consistent especially driving in the evening or at night. In fact, the vibration from the "roughness" of the engine can be felt through the gas pedal. Anyone else here has similar experience?

Les-10

I Agree!

jrct9454

Ours is smooth and quiet - hot, cold, startup, shutdown. Just like all of the MB V6s I've been acquainted with ['98 W210, '02 W203, '08 W204].

RickP330

Hey Guys,
I have the crank knock issue as well. I'm certain that it is a crank / rod related noise.
Just for reference, I'm a Mechanical Engineer and I work on large rotating machinery, we have 16Mw motor generator sets with 70+" diameter journal bearings, and we service several thousand HP worth of Screw Helium compressors. Plus I raced oval track cars for 5 years in my youth, and I have blown up motors before and know what it sounds like. I'm not tooting my horn, I just want to qualify my opinion.
Mine was mostly a hot start issue only. and only after it sat for more then 2 hours. But now it occasionally happens on cold (room temp) start up as well. It really bugs me, but I have great faith in MB, if they tell me it's normal, I'm just going to keep driving it like normal. They have been at this for over 100 years so I know they know how to make engines. Meanwhile I'll keep logging complaints at the dealer every time I go in.
RickP

RickP330

This sounds exactly like what is going on. How did you get the Micofiche slides? Do you have access to service manuals?

Have you persued this issue any further at the moment? Anyone resolve the noise yet?

Thanks
Rick

RickP330

Hey Gang,
I Just want to follow up here, are we all still putting up with the noise or did someone resolve the issue yet?
RickP

Les-10

I'm awful concerned too but am being told it is not an issue & will be checked at my 1k-3k visit as I've only got a little over 700 on it now. Like I stated before, mine made the noise the first morning I started it. Wish I had started it at the dealership for my initial test drive but had no reason to suspect this kind of problem with a Benz. It's hard to ignore, I'll tell you.

C4Life

I have been able to get the "woh, woh, woh" noise by holding the engine speed at 900 rpm in neutral. The noise is the loudest after a cold start but can also be heard after the engine is warm. The noise is also transmitted through the steering wheel when the engine is at 900 rpm. I only have 500 miles on my c300 and have not had it back to the dealer yet. Try holding the engine rpm at 900 and let us know the results!

Les-10

Don't hear it at 900 with mine.

Spec_Davis

Yup i get that studder studder start but it disappears after 5 sec of warm up. i just serviced my C300 i'm 1000k over

wblynch

Most likely it is the variable cam timing. The system works with oil pressure. At first start on a cold engine it probably takes a few seconds to pump enough oil in there to tighten the timing chains.

methodz

how bout instead of starting it right away, put the key in the accessory position for about 3 seconds, then turn the engine. on my old car that would give the car the chance to let the fuel lines to flow. see if that makes any difference whatsoever. i think it was because fuel would retract in the lines overnight, and turning the cars electical on without starting the car would make the injectors move the fuel back to where it is ready to spray on startup whereas if you startup right away you may turn the engine with no fuel for a split second which might be causing the noise at startup.

gpace1

Wblynch, I think you nailed it. I "googled" variable valve timing noise" and was treated to a host of information regarding the subject. Evidently, the Japanese manufacturers (Denso) have resolved the problem by modifying the VVT controller to reset at shutdown. As I interpret the problem, it seems the MB VVT controller oil pressure doesn't reset the controller after shutdown. Maybe still thinks it needs high pressure. So, on startup, the controller has to readjust to the lower oil pressure. That adjustment is probably the noise we hear.

I think I've intellectualized the problem sufficiantly to delude myself into a state of appeasement .

gpace1

Check this site out for a description of a Toyota 4-Runner VVT system. Either our W204 VVT controller is defective or doesn't have the vane locking pin device.


http://www.panavi.kz/4runner/215/NCF...vvtisystem.pdf

narky

Thanks for the helpful explanation! I, too, have been sorta, half-way, kinda, maybe steered into a state of appeasement, thanks to your explanation. And wblynch's as well. I am now willing to live with the fact that when I first start my Mercedes in the mornings, the car believes that it is actually a Ford diesel truck.

But what about the weird *shudder, shudder, putter* that I hear sometimes (not always--even weirder) when I shut off the engine? It kinda sounds like the car is on its last gasps, and is about to die. Not worried, just wondering. Anyone else?

RickP330

LOLOL,
That is exactly how I feel! I don't know if I'm convinced about the VVT yet but I have to admit its a possiblity. Lending a little credibility to this is an article a co worker forwarded to me. You have to scroll down midway to the Mercedes question. Worth a look I suppose:

http://www.newsday.com/classified/au...4903963.column

RickP

PS does a '95 500SL have VVT?
Also, the run on issue could be poor gas, what are you using?
RP

saleswiz

I have owned my c300 since Oct of 2007. Mine had the same engine noise and now 3 years later putting a new engine in!!! 11,000k for a used one. I am very displeased with this and Mercedes definitely has an issue!!!!!!

Carsy

Many thanks for the follow up post. Could you tell us what damage there is & the cause ?

Speakerz

Add me to the shudder issue. I didn't notice anything wrong at starup, except the RPM spike companied by the Ford truck roaring at the first few seconds. I had a Golf before, which acted just like this, so it really doesn't catch my attention until I read other members' complaints. But mine c300 shudders sometimes during idle, which kinds of worries me. I have only 6k, and just had it serviced at dealer 2 days ago. I didn't notice the shudder before the service performed. I suspect the dealer made some mistakes, though I can't be sure. So somebody got that shudder too?

C300Kid

I think we all have it.

I've stopped caring.

dcjwlee

The shudder? I have it at idle too.

@50k now so I'm out of warranty.

chrystian16

I bought a c300 at CarMax the engine make an ugly noise when turned on so i decided to go to mercedes they keep the car for 4 days after 4 days I was told the engine sound is normal
so I went back to CarMax and sold the car.

ESPoff

Hey guys, the quick knocking sound being heard for 3-4 seconds at startup is from the upper main bearings. The knocking sound is heard whether the engine is hot or cold, its mainly heard tho after the car has been sitting overnight. It is considered a "normal" noise but can be fixed, just needs to be researched on the dealers end...

RLE

Upper main bearings? No such thing.

This noise was heard in my '01 C320 with the M112 engine and the same thing showed up in my C300 after I had owned it for awhile. It's present before oil pressure comes up and occurs hot or cold. There have been many posts on this in the past.

I have decided to ignore it.

The dealer claims it's normal, naturally.

ESPoff

The dealer says its normal because Mercedes tells them to say its normal because no harm is going to be done to the engine its just an annoying noise. The knocking sound is from the upper main bearings, theres not enough oil pressure built up during the first couple seconds of startup. The fix is to remove the old bearings and replace them with one size bigger bearings to help build pressure as soon as the engine starts. Ive heard this noise in several 204's including a 2011 with less than 5000 miles on it that I fixed last week by replacing the bearings. Im just letting you guys know what ive done to fix the problem..