Noise on startup - rattle noise - driver side near wiper resevior
Upon start up, more noticeable on cold start, I hear some rattling sound that is coming from the engine area next to the wiper resevoir. I thought there was something loose. I open up my hood to investigate and still hear the noise rattling and very apparent near the wiper resevoir.
The rattle goes away after it warms up a bit or when I gas it while driving. It remains when I stop, when the engine is still cold and goes away when it warms up.
So what is this? Is something loose or broken?
Here's a picture of the location where I hear the noise and pin point it to.

This noise sounds llike diesel engine car kinda rattle. What could this be?
Last edited by 04mbc230; Jul 30, 2010 at 09:32 PM.

Good luck

I am talking about the rattling sound. It seems you can hear it more towards that metal plate in the video. The high enginee noise goes away if I close the hood, but that rattle stays.
http://www.youtube.com/watch?v=S-Z4cfEF4bI
Can here it from the driver's wheel well too.
http://www.youtube.com/watch?v=g_XAJ7itUCg
I read that it could be the SC tensioner or the purge valve?

All this said - I don't like the sound of that at all - it spells trouble. If it's the purge valve you are OK & no harm can be done but most other things could lead to a mess that make noises like that. It could even be the vacuum pump.
Unless someone else has a better idea you should have that properly diagnosed soon. It's certainly not something like a small end bearing or it would become noisier as the vehicle warms up. It could still be timing chain related.
If you want to go on DIYing then get a 6 buck car stethoscope or use a long screwdriver against your ear to track down exactly where the noise is coming from & post. Be careful not to get anything into the moving parts.
You may be able to isolate the noise by putting your hand on various components (ABS pump/unit, Air pump, Power Steering Pump, engine valve cover, etc).
Last edited by pcy; Jul 31, 2010 at 11:52 AM.
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http://www.youtube.com/watch?v=N4Ocq883vuY
The sudden air sound is what I assume to be the Secondary Air Injection system. It's way amplified on this video (not sure why?) and hardly noticeable in person.
The Best of Mercedes & AMG

Have you been revving the crap out of that engine?
Last edited by Glyn M Ruck; Jul 31, 2010 at 08:19 PM.
Also can you confirm in my video if the air sound that happens when I move the camera to the wheel well is the secondary air injection or the blower dumping pressure?
That garage brings a lot of memories Matt
http://www.youtube.com/watch?v=N4Ocq883vuY
The sudden air sound is what I assume to be the Secondary Air Injection system. It's way amplified on this video (not sure why?) and hardly noticeable in person.
Hmmz.. I don't have that sound at all. Funny thing is, I hear that rattle sound as well on your car. It isn't as loud as mine though.
Last edited by 04mbc230; Jul 31, 2010 at 11:44 PM.
I treat this car like a lady and hence she's giving me the whinning as you can hear. HAHA
Last edited by 04mbc230; Jul 31, 2010 at 11:44 PM.
Also you are better off driving it hard sometimes than babying it all the time. My car is rode hard and put up wet - but well cared for.

I am going to bring it in for service and along with the Thurst Arm bushing be replaced.
I am wondering if this will resolve the shaking while between 60mph to 70 mph. Tire related or this Thurst Arm Bushing related?

The castor bushes themselves can't cause shake but can amplify it. Balance your front wheels properly.
I had them to change out the drive belts as well, since it does looks worn out.


I also changed out the drive belts. The car feels tigher now and not as slugglish, or probably it's because it's been a week since I drove her.
Okay, here's the problem. I still here the knocking!! It's not as apparently anymore. I can only hear it when it's in gear. This is what I did and how i notice it. I was manuevering the car back to it's park spot. While I have to turn the steering while in gear, I hear the knocking!!! The darn diesel noise I had before came back.
It seems that this noise occurs in low rpms, probably around under 1000 rpms to get that noise. I had the tech look at it and now it's back to the possible SC tensioner. Arghhh.. i thought this was the issue from the beginning, but he said he was going to change that out but didn't hear any noise when he got to it. He then investiage other parts and hear the water pump had some noise when he spinned it.
I guess the water pump was an issue but wasn't the actual noise that I pinpointed here. So now.. I am wondering if they would need to take out the drive belt again to get to this part.
Do you think I can live with this noise or does it have to be fix soon?


