MBMechanics

Hey guys, thank you for taking your time to read my post. I bought my mom a 02 C240 (W203) and fixed all sorts of stuff on it. Had an electrical issue, sorted it out (flooded computers) , replaced coil packs all 12 plugs replaced the power steering 3 times tensioners, brakes pads tires alignment screens etc. but I have 2 issues I cannot figure out. My mom says when she drives, it squeaks like absolute hell. I drove it and have an audio recording of it. It squeaks like hell while driving and still squeaks while it’s standing still. I thought it was brakes or rotors but they wouldn’t make sense if the car was standing still in park. The car does vibrate if I can remember but it’ll squeak even without vibrating. Second problem is The car does shake back and forth from stop lights and signs sometimes. it also lacks power when taking off for a second then picks right up and lacks power in reverse. When the car was bought from auction it didn’t go into half the gears and we replaced the tranny’s computer and it shifted perfectly fine. Do you guys think a transmission fluid flush would fix that? I have no idea what the squeaking can be but I was thinking maybe a vacuum leak. My mom states it does it every time on a certain turn she does but does it all the time regardless. Sorry for the long write, I tried explaining it as thoroughly as possible to make it easier for you guys.
thank you for your insight and help!
Mack

KevinH2000

I suggest that you check the motor and transmission mounts. Defective motor mount symptoms.

This thread has some additional suggestions.

Good luck.

MBMechanics

That’s what I was thinking I had bought 2 motor mounts and a transmission mount and want to install them hoping the vibration gets removed. Is there an online service guide that the shops use for directions on how to do this? I’ve replaced mounts on suvs and such but never on a benz
thank you so much for responding.

KevinH2000

This site has many useful documents.

If you don't find the information you need, you can buy a copy of the Mercedes WIS (Workshop Information System)on an auction site.

MBMechanics

awesome thank you so much for your help Kevin. I hope you have a great day

C230 Sport Coup

Sounds like the illusive OokiTooki bird's mating call.
I can't imagine that would have to do with motor mounts.
Really want to do mine, but not an easy job.

C230 Sport Coup

Has anyone suggested checking your power steering fluid level?
Thats what it sounds like to me, especially if it's more pronounced when turning.
Be sure to get the right fluid, the CHF stuff in the green can or from the dealer.

MBMechanics

yep I replaced it 3 times and checked the fluid again too. When I replaced the first one the seal was bad and it lost power steering fluid killing the pump but it was remanufactured so I think that has something to do with it. I bought a brand new one and a new seal between the reservoir and pump and it stopped leaking. I’m using CHF11 and that stuff is not cheap whatsoever here in California xD. Ran me 55$ a bottle. I check the power steering everyday for my mom and it’s not loosing a drop. The sound it’s making is so weird and high pitched to the point where I could only think it was a CV axel, but it does it randomly and not constantly and does it while at a complete standstill

MBMechanics

yep, I am currently doing it as we speak and it is a complete nightmare. I’m currently fighting the exhaust manifold after just fighting the exhaust and it leaves me very little room to do anything. I bought the parts 3 months ago but put off doing it because of the headache of a job it is xD

MBMechanics

Man I’m still on the exhaust manifold as it is fighting for its life to stay on. The corners and little nooks and crannies make it impossible to do so. Anyone know if I need to move the whole exhaust? I’m on the last bolt on the manifold but have been struggling with it for 45 minutes

slammer111

First, I would check the blower fan. If you turn off the HVAC system, does the squeak go away? (this system is basically the same for all W203s give or take)

Your MY2002 has a different engine (M111) from MY2003-2005 (M271). So hopefully the stuff I'm listing below applies to your car.

Next, I would check the one-way alternator pulley which is known for seizing. I remember the car would make a chirping noise if the AC was on and the car was in gear but not rolling.

Here are directions for replacing the engine mounts. Call the dealership to get the correct PN. Also you may need a special wrench because of the limited clearance (once again, I am not sure for your particular engine). There are 2 mounts for the engine (towards the front of the car), and 1 for the transmission (towards the back of the car).

MBMechanics

awesome I’m going to check the alt pulley right now. When the AC is on it is does the noise sadly so I’m not too sure if it might be seized but I will replace it just in case. I had to buy a specially angled wrench to get to the back exhaust manifold bolts. The exhaust manifold was 100% the hardest part is this job xD once I got the manifold off, I jacked up the engine and got those mounts out within minutes. Installed the new ones and torqued them down within 15 minutes. Here is the old and the new one. I also replaced my transmission mount that was extremely easy. Do these mounts look to be the reason for the vibration constantly in the chassis?

Edit: the transmission mount didn’t look too bad. Definitely was sagging and probably could have caused some type of noise. Only had half an inch clearance from the bottom