I just got my C63 back from the shop and noticed that when the car is standing still (in park, or in drive while braked) the car shakes enough that it's noticeable and annoying. The car has about 3800 miles on it, and I'm positive this shaking wasn't there at all before they serviced it.

It's also possible that when I rev above about 4k rpm, there's a whining sound that wasn't there before, but I'm not 100% sure this is a new sound. I didn't drive the car from Saturday to Thursday, and have meanwhile driven other cars, so my memory could be off.

I brought the car in because the check engine light was on, and I still need to talk with the service guy to get clear on what work they did, but here's a quick attempt at a summary based on the service note:

- They report finding that the "inner rib of the belt" came apart and broke wiring in the left front of the engine.
- Removed the AC compressor to unplug the oil temp sensor to give slack for wiring repair.
- "R&I" electric fan.
- Replaced "serpentine" belt.
- Replaced left exhaust cam sensor.
- Codes were 0765, 0485, 3716, and 0766.

I'll be calling the service guy to discuss this tomorrow, but any thoughts on what they might have done to cause the shaking, and possibly also whining sound?

As far as the shaking, my layman's speculation is that, when they took some things apart and then put them back together, they somehow threw off the balance of the engine (idles at about 600 rpm, which is the same as before).

As far as the potential new whining sound, I have no idea what the cause could be.

Any insights or advice would be much appreciated!

I'm getting annoyed at having to deal with this on a car only 2 months old, but not enough to stop loving the car. After driving other cars for these past few days, the power of the C63 feels pretty stunning (did a quick test drive of an M3 convertible today, and the power/torque isn't even close, but that's another story ...).

 

Is the shaking constant or intermittent? I'll get a few little 2 second rumbles for about a min after a cold start but nothing that lasts.

 

So far, it's constant. Happens every time the car is stopped or parked, and lasts as long as it's stopped or parked. The shaking may even be there when the car is moving, but hard to tell with the other vibrations resulting from the car being in motion. And now that you mention it, I think I did used to get those brief rumbles too, but like you said, they went away quickly enough that I didn't make anything of them.

 

check to make sure they didnt overfill the oil. if i remember correctly thats what was making mine do that.

 

Thanks for picking up on this.

In another thread, I mentioned that the "check engine oil" light had also come on, I had checked the oil and found it to be just a little below the min end of the range, and dealer claimed to have added about a quart. I forgot to mention all that in this thread.

I just checked the oil, and it does seem to be a little above the max end of the range, so maybe they added significantly more than a quart.

In the morning, I'll check the oil again (to make sure I'm not misreading), and will also check the shaking again. If either is an issue, I guess the car has to go back to the dealer ...

 

This is an issue reported by many C63 owners including myself. While many people had the same symptons the origin is different for some cars. My shaking(excatly what you described) was caused by a "lean condition" from my K&Ns.

I need to mention that this happened to me in AZ at 110 degrees with 91 oct and at altitude which is really not the best healthy set up for any car. My shaking went away putting back the stock filters and having the dealer "reflash" the ECU.

Good luck!

 

Same here. Mine was overfilled by a QT.

 

Ot sorry, car looks great

 

My car is stock, but it was over 100 degrees here in Maryland yesterday, so that could be a factor, though I recall the temp being in the 90s last week and the car didn't shake.

So three possible causes identified so far, looking at only factors which have changed since I took the car to the shop:

- Overfilling the oil.
- Something related to the work they did with belt, wiring, sensors, etc.
- High ambient temp.

Thanks for the info!

 

Mine only shakes for about a min. on cold start from over 1k rpm to 600rpm. Then it settles down. The heat is making my car feel sluggish than it was in Jan. I think heat is a factor in your shaking. If you have aftermarket filters also.

 

Just checked the oil and shaking again (after the car was sitting overnight).

The oil still seems high, though it's a little hard to tell because the oil isn't dark so it doesn't leave a sharp line. Plus the dipstick wiggles around a lot when being inserted and removed, so that can cause smearing. But I'm pretty sure that the top plastic marker on the dipstick is submerged, which means the oil is too high.

The shaking is also still there, both after starting the car and after a short drive. Not quite as much shaking as yesterday, but definitely more than before the car was serviced. And the ambient temp is also a little cooler this morning, so that could be a factor.

I'll plan to take the car to the dealer tomorrow to have them check the oil and siphon some out as needed (yes, the same people who may have overfilled it in the first place!).

Meanwhile, any other thoughts would be appreciated. You guys have already been a big help, and I don't know what I'd do without this forum.

 

When you get new belts, sometimes those belts need to settle in and this may cause some shakes...If your oil is ok, and you see no check engine lights, for the meantime drive it and see if it improves. These cars are very "check engine light" sensitive, meaning if you have an issue a light will go on. Be patient.

Edit: You MUST be certain that your oil is not overfilled. Take her in and have them let some out. THIS IS THE PRIMARY REASON.

 

Refer to THIS thread.

 

Thanks, good advice.

I was also thinking of giving it a few days before letting the car go back in the shop. Only catch is that I'm planning to drive from Maryland to Connecticut later next week for AMG training, and I don't want to run into a major problem while on the road.

I agree on the oil overfilling, and am going to take it in tomorrow morning for that. Did a little reading on the web and found that overfilling can cause problems much worse than shaking.

 

Thanks, I read through this thread and it seems (?) like my car doesn't have problems as serious as this. The shaking isn't violent, but enough that it doesn't seem normal either.

 

I went to the dealership this morning and they confirmed that the oil was overfilled (yes, the same people who overfilled it in the first place! ). They also ran a diagnostic and everything checked out.

After sucking out the excess oil, I would say the shaking is now at least 80% gone. Maybe even 100% back to the way it was, but I can't say for sure. There's still a tiny bit of shaking, which may have always been there, but hard to judge now that I'm hypersensitive to it.

So I think that overfilling the oil was the main cause of the problem. High ambient temp may also have been a factor, since it was around 100 degrees yesterday and Thursday, whereas today it's in the eighties (but there was still noticeable shaking this morning before removing the excess oil, though maybe a little less than yesterday).

The tech also suggested that bad gas could be a factor. When I picked up the car Thursday evening, the tank was almost empty. It was after filling the tank that I really noticed the shaking, but I can't rule out the possibility of shaking before getting the gas, since I was focused solely on getting gas at the time.

The tech didn't think the work they did with the belt, wiring, and sensor would cause shaking, but he couldn't completely rule it out.

As far as why the belt frayed in the first place, no one really knows. I don't see any indication that pulleys were wobbling or misaligned, so a defective belt seems more likely. But I'll continue to keep an eye on the condition of the new belt, just in case. Last thing I want is a broken belt while I'm on the road.

So, overall, I'm going to assume the car is now fine, but will continue to keep on eye it.

Thanks again to everyone for your help in dealing with this!

 

Follow-up question: is the "exhaust cam sensor" the same as a "crankshaft position sensor"? If so, sure seems that a defective sensor could cause shaking:

http://en.wikipedia.org/wiki/Crankshaft_position_sensor

"A bad crank position sensor can worsen the way the engine idles, the pistons fire, or the acceleration behaviour. If the engine is revved up with a bad or faulty sensor, it may cause misfiring, motor vibration or backfires. Accelerating might be hesitant, and abnormal shaking during engine idle might occur. In the worst case the car may not start."

 

I get this same issue when the dealer puts in too much oil. The problem goes away after a while as the engine burns off the excess over time..

 

Where was your oil level on the dip?

 

The top plastic marker was fully submerged, plus the oil may have been just a bit above that. The tech said they usually try to keep the oil level right between the two plastic markers, which is where it is now. And I would say that the shaking is basically gone now, so the problem seems to have been caused primarily or entirely by overfilling the oil. Glad at least that it was an easy fix!

 

From everything I've read and heard, I'd remove any excess oil right away, rather than waiting for it to be burned off. As odd as it might seem, excess oil can cause serious engine damage:

http://townhall-talk.edmunds.com/direct/view/.ef18c65

 

A bad crank sensor would have thrown a code I would imagine