About 5 minutes after starting and sitting at a stop light, there was a very loud high pitched whine coming from the the rear. It almost sounded like screaming power steering but clearly from the trunk. It lasted about 15 seconds and quit. It did it another 6-8 times while both driving and idling but got progressively better. I have not heard the scream since. However there is now a mid level in volume hum that seems to get a little quieter as I drive but never goes away.
I opened the trunk while at idle. The noise with a vibration is coming from
in front of the antennna motor but behind the left rear door almost directly above the wheel well.
Other than the noise it seems to run great.
Fuel pump or sending unit issue? Any suggestions of what to look for is
appreciated.
I am much better at going to a mechanic than being one.
Thanks
bill

__________________
85 300TD

88 560SL

05 SL65 AMG

The only other thing in that area that could make noise is the sunroof motor. You'll need to remove the trim panel to get access to it.

__________________
82 300SD 202K
82 300SD 233K
83 300TD 340K
82 300TD 98k euro (parts on the hoof)
85 300TD 282K
83 300TD 197K

Don't the SD's also have an electric vac pump in the trunk? Someone else here probably knows better though.

__________________

Yes, but it's on the other side.

The only other thing close is the sun roof motor.

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83 SD

84 CD

OK.
Just went out to try. Opened the trunk and started the car. The noise
(Hum) is now also gone. Guess what no longer works. The sun roof will
not open. I can hear it trying (there is the normal sort of whirr sound) but
the sun roof does not move in either direction. It is not used often but I did have it open briefly the day before maybe.
I will do more research but am sure I will be back with more questions.
Thanks especially to Johnt49 and Toomany MBZ for pointing the compass.
Bill

one more thing. Since it sounds like it is trying to open, do I assume it is a broken sun roof cable rather than the sun roof relay or sun roof motor?
Thanks again.

__________________
85 300TD

88 560SL

05 SL65 AMG

It would be a good idea to unplug the sunroof motor until you find out what's going on. No need to risk more damage or a possible electrical melt down! You might want to check the rocker switch to see if it's returning to the middle (off) position and not sticking. Also it could have an internal problem (broken contact floating around inside) causing it to run the motor.

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82 300SD 202K
82 300SD 233K
83 300TD 340K
82 300TD 98k euro (parts on the hoof)
85 300TD 282K
83 300TD 197K

Thanks.
I neglected to say it only tries to open when I press the rocker switch to
open or close. In neutral position, there is no sound at all. I will
unplug it anyway.
Bill

__________________
85 300TD

88 560SL

05 SL65 AMG

After checking with a couple of highly recommended repair shops, I decided to have what I thought was a broken cable or mechanism, replaced. When I arrived, the techs realized the sunroof system was a bit
different than they thought. They did give me info on a repair kit available for the drive unit which makes it no longer necessary to replace the whole unit. However they felt they did not have the expertise or tools to fix it for a reasonable cost.
They then called another local shop (Sun Valley Imports in Tempe, AZ)
and asked if they could work on it. One of their technicians seemed familiar with the problem, so I took it there. They said it would take about 30 to 60 minutes to figure out the exact problem.
After 45 minutes, it turned out that the transmission for the sunroof needed adjustment and the cable tension needed adjusting and the track and slides needed lubrication. An hour's worth of labor and no parts later I was on my
way with a working quiet sunroof. I was envisioning a several hundred dollar repair bill. Sometimes it is better to be lucky than smart.
It is also nice to stumble on to an ethical shop with knowledgeable techs.
Thanks again to the Forum members for pointing me in the right direction.
Bill

__________________
85 300TD

88 560SL

05 SL65 AMG

Glad to hear it was that simple (after reading other threads of doom & gloom)

Post the shop (or check to see if they are posted) in the "Good Mercedes shops" section!!

will do.

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85 300TD

88 560SL

05 SL65 AMG