Hello everyone,

please excuse my bad English, I sometimes work with a translator because I'm from Germany.

I drive a 2012 SLK 250 CDI, but since this is related to the W204 in many areas, I'll post my question here in this forum because there may be more people here who may have heard something like this before.
To make it easier to understand, I filmed and uploaded the whole thing.

When I steer to the left while stationary, I hear a kind of hissing/whooshing coming from the front of the car.
The noise can be heard on the inside of the steering column/footwell, but also on the outside next to the two front wheels.
This hissing occurs primarily as soon as you turn the steering wheel to the left faster.

Here you can hear the sounds well from the outside:



Here you can hear the sounds from inside from two perspectives:



The freewheeling of the alternator has already been checked in the workshop and found to be OK.
The oil level of the power steering looks OK based on the dipstick on the cover.

As I have never heard a noise like this I would be very grateful if you could take the time to watch my videos and give your guess or opinion on this as I have been desperate for a solution or explanation for the noise for quite some time seek.
Maybe you can test/check that on your vehicles for comparison.

Thank you in advance and best regards
SLKer

PS: The noise occurs constantly in the above situations and is therefore independent of the engine or outside temperature and it is not the familiar noise at the end stop of the steering, there is a slight whine from the pump, which I consider normal. It is therefore not a howling or yelping that one often reads in relation to the power steering.
Maybe you can test/check that on your vehicles for comparison

 

Lol. Your English is better than some of the people I know that were born here. No clue to your question, however.

 

How many miles/kilometers on your SLK? I suspect that many just consider this minor and ignore it like I did until the noise became intrusive at 180-200,000 miles. At that point the offending component, in my case the pump, became easier to identify.

 

If the power steering fluid is the CORRECT type and the level is good, then it may be the pump starting to fail. However, I don't think this would be catastrophic as you should still be able to steer. Have you had any service done on the steering system before this happened? How long has it been this way? What were the conditions when you first noticed this?

Sorry, but I could not hear the noise (the Diesel was too loud). I also could not hear anything in the other two videos.