S70Houston

Need some help identifying a slight squeak/squeal which has suddenly appeared on my sons 2004 C320.

It is a very quiet sound, not continuous, more like a “morse code” sound. If you roll the window up you cannot hear it. Comes and goes, when one accelerates, the sound as well increases in speed, seems to be coming from the front left wheel, but not totally sure. Definitely on the driver side, but it is hard to exactly determine with the window open and the wind blowing while driving.

Any ideas what this could be?

Thanks in advance.

slammer111

Wheel bearing comes to mind.

Jack the car up and give the wheel a shake. Any play means the bearings are loose (can be tightened) or replaced. Hub may be damaged too.

If it's a tapping noise, it's the purge valve.

At this point I assume the sound doesn't appear when the engine is running and the hood is open.

S70Houston

Thank you very much Slammer, much appreciated.

Correct, the noise only appears when the car is moving/the wheels turning. I as well thought about the wheel bearing, but was thinking that the noise should be louder and more of a “grinding “ noise.

Questions:
- Is it dangerous to continue to drive without addressing this right away?
- Will more potentially get damaged if continue driving?
- How do I tighten the wheel bearing? Do you have any instructions?

Again, appreciate your help and support, thank you very much.

slammer111

Anything is potentially dangerous. The part can catastrophically fail in a year or in a day. That is a decision only you can make.

If it's a control arm ball joint, you probably have a few months. However, if it's the wheel bearing, I would get that looked at ASAP.

Another potential source of sound is the brake pads. Jack the car up and give the wheel a spin. This one will make a light scraping (rubbing?) noise at the same wheel orientation (ie every 360 degree turn will make the same sound). If this is the case, there is nothing to worry about as long as the pads aren't worn. If the disc is warped or somehow not true, there will be a pulsating feeling (a pulse for each turn of the wheel) when braking.

The wheel bearing can actually be tighened. Just pop the cover off and the C-shaped clamp nut is right there. While everything is right there you can freshen the grease inside. Torque for the clamp nut bolt is 11Nm.

S70Houston

Thank you very much again slammer.

112233

Jack up the wheel,put your hands in 9 am and 3 pm position, wiggle, 12 and 6 position, wiggle. If you hear/feel any play, you have an issue. Spin the wheel, the wheel should make not any suspicious noise.
Put your fingers along the spring and feel for any cracks of the coil, usually it is the lowest turn.
I think, this morse code noise can come from a sway bar connection rod, try to wiggle it, too. Good luck

S70Houston

Thank you very much.

It is on the agenda today to check this all out.

S70Houston

No noise when spinning the wheel, no loose connections anywhere, no crack in the spring.

No feel of any play at the 9 and 3 position, slight wiggle at the 12 and 6 position.

Wheel Bearing Issue?

S70Houston

Slammer?
112233?

slammer111

Sounds like wheel bearing play. Time to open up the hub and see if the bearings are damaged. If you're lucky, it's just a loose clamp nut.

The good news is that MB sells a wheel bearing kit and it's surprisingly inexpensive.

S70Houston

Many thanks Slammer.

112233

Sorry, different time zone, europe, yes, wheel bearing. You can probably correct the play, but usually you need a new one. To verify the noise it is probably a good idea to tighten the adjuster nut first.