akbro93704

When I started my car this morning, I noticed that the engine was randomly "shaking" during the high rpm warm up routine. This is the first time I noticed these random shakes...it feels like the engines moving side to side. This is the first car I had that takes a long time to cool down, sometimes if the car sits over night it still will have a normal, warm start start-up. My old S40 would do the high-rpm thing if it sat for more than an hour or so. Any comments are appreciated

PhaseNine

If you engine is moving alot and you beat on it sometimes while driving, check your motor mounts that might the a problem, but this is only if its moving alot.

comanche

Hey I have the same exact problem
I just bought my c300 two weeks ago and it does the same exact thing on a cold start

jtec19

yea mine does the same...

cvx5832

Same thing here. It gets better as it gets broken in. I'm at 12k miles, and I can barely feel it now even after a really cold morning.

Paolo

shinyroo

Yup, mine does the same thing!

akbro93704

Okay. Well its good to know it's "normal" I guess? It didnt do it today, only does it on random occasions. Weird.

Rixter

..this is typical benz behaviour... nothing to be alarmed about...

RickP330

My car does alot of bizzar stuff when I start it. I LOL when somone posted that there C300 thinks it's a 7 Liter power stroke desiel for the first 3 seconds when it starts - because that's exactly what I was thinking. 15K now and no problems otherwise. I just accept it...
RickP

CarGuru

My car does it too! and the exhaust sounds extremely throaty for some reason also while this is going on. Mine only lasts for about 10 seconds then goes away and is really smooth.

-Ryan

Tazwell3

mine shakes too, especially when I don't drive if for awhile.

C300Sport

Good to know I don't have a problem...at least i'm not alone anyhow...

Les-10

I know how you feel. Bothered me big time until I learned I had plenty company.

Sarabenz

I bought a 2010 C300.. I have so many problems with it. It shake in the morning, I develop a backache when driving more than 20 minutes, the car is not smooth and feels every bump in the street, Overall, I am not happy..

jctevere

^ Try lowering your air pressure or something, I have found that the w204 has very comfortable suspension compared to competitors.

As far as shaking, mine does this too, I find its not as bad when you use 0-w40 Mobil 1 oil, and doesn't happen as much, but it still occurs. Still normal and ok @ 40k miles. Also, I notice that the RPM's "vary" as in the needle bounces, even at a contant speed on a straight slope. It is even more "audible" and can hear the variance since I got my exhaust done.

dgghostkilla

Damn. I car does it sometimes. I actually thought it was something to just continue to monitor. But after like 8-10 "mine those that too" I guess it's nothing to worry about

Acapulco Bill

Strange. My 2010 C300 is so quiet and smooth on startup I make it a point to pay attention to the tach just to make sure the engine is running. Which is disconcerting, as the tach itself takes a couple of seconds to wake up.

As for the shaking, one would suspect an injector fault. A check for error codes would show this defect. Engine mounts - is it possible that different assembly lines source the mounts from various suppliers? Shaking during cold weather starts, if not the injectors, would indicate defective mounts, as the rubber is harder and should support the engine more firmly at lower temperatures.

RLE

And yet my '08, coming up on 30K miles, has never done this, hot or cold. Nor does it increase rpm on a cold start more than 100rpm.

It's a defect but if you want to live with it, well then..................

lfilomeno

Mines did the same thing after a month of purchased. I truly panicked thinking it was something really bad. Called the service advisor and told me that was completely normal. In my case the shake last probably from 3 to 4 seconds then go smooth. Only happens in the mornings (cold start).

jctevere

You probably garage your car, if not, the cold start holds RPM upwards of 1,000-1250 initially, then around 800-900 before settling at the 600RPM idle rate. Since yours is garaged, the car is somewhat "warm" and doesn't have to increase engine RPM as much or for nearly as long. The lifters almost immediately relax.

But for people who park outside or in the cold, this is normal to have RPM's increase at start up and for some uncomfortable shaking.

Rami1212

I am just surprised of the number of people who are facing the same issue of the engine shake as mine does the same.
when im starting my engine on a mid cold temperature most of the times it starts shaking like a holy coaster even the passengers can feel it and after visiting the dealer several times a sensor has been changed and it is still there and at last i was told its a fuel injection issue and advised me when i check in for my 45000 k service to mention the issue so next week im checking in as im 500 k away from , also on rough idle i have a vibration .. Any how on a conclusion mercedes disappointed me

Mr.Mango

^ you likely have a motor mount issue. Try shifting from park into reverse or drive, if its motor mounts the shaking should get substantially more aggressive once there is load on the powertrain.

This can also happen on cold start as the engine high idles to 1500rpm or so which produces similar load to that of transmission engagement.

Rami1212

Thanks for the input .
What i believe this is a defect in all mercs by the factory as it is not logical to have this similar issue by this amount of ppl, also the engine mount is not just something normal to have it replaced while the car is still one to two years old.
The shake starts when rpm goes down to 700rpm where the rpm needle starts to shake , also the engine light comes up from time to time.
Im gonna bring it up next time i check in the car into service and i hope to figure it out before my warranty ends.

2nice4me

good luck, hope it gets fixed for you. my w204's had a slight increase in RPM and a somewhat rough idig sound which disappears after 10 or so seconds.

for your issue i would just have your camera ready and take some video and sound clips as evidence

Trancebolt

"Thanks for the input .
What i believe this is a defect in all mercs by the factory as it is not logical to have this similar issue by this amount of ppl, also the engine mount is not just something normal to have it replaced while the car is still one to two years old.
The shake starts when rpm goes down to 700rpm where the rpm needle starts to shake , also the engine light comes up from time to time.
Im gonna bring it up next time i check in the car into service and i hope to figure it out before my warranty ends."

No defect. Its just a method of the car getting itself ready to go. Mine does it from time to time irrespective of the temperature of the weather or the car.

Motor mounts are all user error. You could ruin them in one day if you drive badly and carelessly.

If it only rumbles temporarily while turning on, and a few moments after its totally engineered to do so.

Similarly, people complain of brake rumble when sitting still at a light or something after driving; Its simply a brake cooldown process the car does and it makes people feel uncomfortable. It only does taht dependent on weather and the stress on the brakes that day. Keeping them fresh.

my dads sold mercedes for a long time
My dads had people complain of both of these things and they do not relate to any engienr trouble. however, people do often misdiagnose health symptons the same way they do car symptons. Alot of problems sound or feel the same as symptoms related to many categories of issues.