Hi, I am the new owner of a 94 C280. Got a good deal on it, has low miles, so I invested in a new entire engine wiring harness replacement to take care of the rough idle I was having. Apparently this year and model had problems with the usage of "experimental biodegradable wire covers" that could not withstand the engine heat, hence short issues. Anyway, though that problem seems to be resolved, I am now noticing an odd 'whirling' noise when I drive above 40 miles an hour. It seems to be coming from inside the car, right passenger side. It's not the heater, not the radio.....It almost sounds like a casette tape rewinding. It was very apparent yesterday; today, not so much, but still on and off. It seems to be intermittent, and it is VERY annoying. Any experience?

(Also, a side note: After having the harness replaced, my turn signals are intermittently not working. Called the mechanic who did the harness job and he thinks maybe there is a loose connection, so I will have that checked out. Any experience with THAT issue?)

 

was the sound coming from underneath the car?

was it really speed related?

 

Hi Sleepwalker,

Thanks for responding.

Yes, it was speed-related. It seemed to be only over 30-40 miles an hour. It seemed to be coming from the right passenger side, but it was difficult to pinpoint it. When I turned my head right and towards the back, I could not hear it as loudly.

Last night it didn't make the noise at all. So strange.....

 

I also am the new owner of a 94 C280. I also notice a 'whirling' noise in my car. When I bought it in August I didn't hear the noise at all. Now I'm noticing it more (I surpise becuase of the lower temperatures of Fall and Winter). My 'whirling' noise is exactly proportional to the speed which the vehicle is traveling, but seems to be loudest between 5 to 40 mph.
My guess is that it is the speedometer cable. Perhpas the grease has 'dried out' in the speedometer cable and that's what's making noise. Can anyone confiorm this? And if so, how do I relube the speedometer cable, and what lube is the best to use?

PS- Casamama, In case I have similar problems, where did you get the new wiring harness, and how much did you pay to have it put in? Thanks.

 

Hi, I actually went through the dealer who sold me the car - supposedly in perfect condition. I had it for one day when the car started missing during deceleration and during idle and the problem was then discovered. Through him, I was able to get a brand new harness through Mercedes Wholesale for $500. My regular mechanic could only get me a used one for over $600. Plus, the dealer's mechanic did the labor for $200. My mechanic quoted me $1200 for the entire fix -- so I saved $500 overall. Now I have a brand new harness and the car is running like a dream. Oh, and the whirling now seems to be gone. Except I NOW have a weird speedometer issue I posted about today and am hoping somebody can help me with.

 

Its your speaker swirling, is your radio on and turned all the way down the speakers get energized and make that swirly noise with the engine rpm's the slower you idle the louder the swirl the higher the idle the louder the swirl, my car does same in rear speaker behind driver, how do i fix that

 

noise supressor.

if alternator diode is bad, this static noise is heard.

 

I own a 99 c280 and I'm experiencing the same noise. It definately seems like the sound is coming from the passenger side. The sound gets louder and higher pitched when driving from 0 to around 40 or 50. Once im going quick enough liek about 80 I think the outside wind and other sounds tend to block the sound so that I do not notice it as much. The higher the rpms the louder it gets. Can someone help me out?

P.S. It does sound much like a tape being rewound... or those old toy cars where you run them against the ground a couple of times and then let them go and they will go by themselves.

 

anyone got any ideas? the sound is driving me insane