C32MOOSE

I did the vaccum leak test yesturday and doesn't seem there are any leaks at all. so i'm back to square one.

i'm beginning to think maybe the engine mounts/trans mounts weren't tight enough? not sure what else i can check, i believe i've tried everyone's suggestions so far? let me know if you might have any other ideas, as much as i enjoyed troubleshooting, i'm close to taking it in and get it resolved. thank you everyone for trying to help me with this issue.

slammer111

Did you torque them to spec? Top bolt 50Nm, bottom bolt 35Nm for the I4. The values should be similar for your V6.

C32MOOSE

So quick update, the vibration has like i said only gotten worst after changing my cv axle from oem to after market. On the benzworld forum i found out thru an experience mb tech that aftermarket cv axles do indeed cause vibrations and specifically the ones i'm speaking about. So @slammer111 you're right for asking about the OEM cv axles it seems that i need to replace my aftermarket ones, now my new issue is finding OEM ones or something equivalent quality, does anyone recommend or can link me to where i can buy them, i'm not having any luck researching them, and i don't know the full PN for the part either, i basically need the cv axle assembly OEM or high quality for 2005 C240 4matic. Front Passenger side. Anyone's help is much appreciate it, sorry for coming back to this but i believe after all i've tried, this has to be it.

slammer111

Where are you located? You might want to put that in your profile.

I'm assuming you're in USA. In that case, look at RM European or FCP Euro.

C32MOOSE

i'm in chicago, us. Just wanted to say thank you all for all the help, the issue was indeed the CV Axle for anyone still following this thread. The old one was bad for few years apparently and most possibly damaged the OEM CV axle on passenger side front. I changed it with an aftermarket one and vibration got worst. Today i found a used OEM one in a salvage yard for $100 in great shape actually. Changed it this morning and boom, vibration completely gone. I also read about this issue in other forums as well just never really believe CV axles would cause vibrations like that. Now i know. Thank you all for the help again, Issue resolved

Dillinator

I'm having a similar weird problem with mine too. I have an '05 c230 1.8L Kompressor 5 speed auto and sometimes when I come to a stop the car will bog and almost try to stall and the revs will fluctuate as if the clutch is grabbing and releasing at a stop. It stops when I go into neutral but it also happens when I turn the wheel full tilt in either direction when moving around 1-5mph. I have not the slightest idea of what would be causing this, other than maybe the transmission fluid needs to be replaced??

C32MOOSE

i would check the power steering fluid first, make sure that's not leaking or needs to be topped. it's different issue for sure, if that's not it, i would guess the issue would be around the wheel hub, maybe rotors, ball joint. i'm not mechanic, but as an engineer, that's what i would think based on the info you gave him. I'm sure one of the other guys can help you much better though.

slammer111

Check the alternator pulley and replace if necessary. They're known for seizing. Because of the way the pulley and serpentine system works (YouTube is your friend), it creates problems with engine operation at a) low RPM such as idle, and b) during quick deceleration (specifically an abrupt decrease in engine RPM), both of which you have just described.

Transmission fluid isn't causing the problem you're having but it wouldn't hurt to change it out if you've never done it. Contrary to what the dealership says, it is not a lifetime fluid. Official (outside of North America) service interval is 60k km, though personally I think that is a bit excessive. While you're at it, make sure you have the latest pilot bushing. Older versions are known to leak (bad o-rings) and mess with the transmission controller. Dealer will have the latest one. Part is cheap too.

Lastly, make sure your crankcase breather hoses and check valve are in good working order. There was a worldwide recall in 2008. Give your VIN to your local dealer and see if it has been done on your car. If it hasn't, the dealer will do it for free (recalls do not expire). Cracked hoses can cause rough idling. On my car, I had to do this job a second time. Looks like it has to be done about once a decade.

Dillinator

Thank you this is super helpful! After hearing what you've said I'm 99% certain that must be it especially because it happens much more frequently if I have to suddenly or abruptly brake for some reason. I apologize but how would I go about determining whether or not it is bad? I'm only 17 and I haven't done any work with an alternator yet.

About the transmission fluid, you're right it would probably be a good idea to change it because I've only owned the car for a little under 2 years but I am unaware as to whether or not any of the previous owners changed the fluid.

Also, about the recall, I already knew about it but I had the car sent into my local Benz dealer around a year ago for NHTSA recall #19V918 and I could've sworn I asked them about that one too but I might be wrong considering I just looked up the VIN for my car and apparently the only recalls which have been done are #19V918 and the one regarding the drivers side airbag. I'll definitely give them a call and figure that out, thank you!

Dillinator

That's a great idea as the steering has been noticeably stiff for quite some time. I figured something must have been wrong when I realized that my 1961 Studebaker takes less effort to turn than my Benz! In July of last year I had an accident where the outside ball joint came out of its socket on the drivers side lower control arm -> https://mbworld.org/g/picture/20136441 Then in August I replaced the upper and lower control arms and the sway bar connector links for both the drivers side and passenger side, and I'm pretty sure I would've noticed had there been an issue with the hub or rotor, unless you're talking about the rear hub(s)/rotor(s). What exactly would I be looking for if I went and checked them? (i.e. rust, general wear, cracks, etc.)

Jason Mclaren

i had this exact problem and it took me about six months to find while replacing almost every mount or suspension part. ive yet to see anyone correctly identify it if its the same so i suggest you check out the two rear bolts on the steering rack. i dont know how and my mechanic cant explain how the nylock nut could come loose enough to release enough for a rattle but it did. i had him tighten it on the lift as this is acutally a two man job. and lone behold a year later that rattle is back this time im going to use the red locktite and be done with it. hope this helps

jggarcia.vc

If you are having vibrations while braking it could be the vacuum pump located right behind the engine it's a tight fit but it can be replaced I replaced mine and the shaking almost went away. The last thing that I did to remove the shaking (rough idle) while in Drive or Reverse is clean the throttle body tons of build was on on it and once I did that car runs 99% new.

@C32MOOSE have you tried cleaning out your injectors with or fuel system could also be a reason for rough idles just watched a video on all of liqui moly products going to try them on my next service.

tedi

yo

slammer111

^ The problem was traced to a low quality aftermarket CV axle. He replaced it with an OEM one from a wrecker and it fixed the problem. See post #55.

Adventurer129

Hey, great info in here. My mom’ C320 started vibrating and had engine mount replacement. Still vibrates. The mechanic consulted with MB dealership and got new mounts from there…still vibrated
Then I read this blog and talked to the mechanic about getting Lemfourder mounts-even sending him the link to this blog. He got Lemfourders and my mom just texted me the vibrations are gone !

slammer111

The R one actually looks like the OE version which were installed on my car. They've since updated the design since to the L one, but I wouldn't be surprised if they still sell the R one.

Aftermarket are fine as long as one sticks to reputable brands that are actually known for making engine mounts. Another example besides Lemfoerder is Corteco. Corteco makes plenty of other rubber products (examples include rear transmission mount as well as steering rack grommets) for the W203 as well as other German cars.