Speedometer? Cable? This winter stinks! - PeachParts Mercedes-Benz Forum

Zerohour3k · #1 01-21-2009, 10:12 AM

If one more thing goes wrong this winter, I think I might just freak out and do something stupid, like buy a Hyundai out of spite.

Driving to work today was the same as usual, mostly. Start car, shiver, start driving, relax as the heat finally comes on, enter the highway, shake fist angrily at the terrible drivers. Now, my speedometer is fairly accurate (It's always been about 5mph fast when checked against GPS, but I think that's normal), and has never really given me any issues in the past. I know my cable is probably on its way out, since even in the summertime, my needle bounces until I get up to about 15mph. On extremely cold days, the needle will sometimes get twitchy at about 70 to 74mph, but smooth out again at 75. Odd.

Well, today was a little different. I got on the highway, drove for about 15 minutes @70-75mph (car is nice and toasty warm at this point, it's 20f outside), and was rather suddenly greeted with an extremely loud whine from behind the cluster, causing the speedometer to fluctuate wildly, and kind of "glide" from position to position. I panicked and pulled the car over; the noise stopped. Started driving again, and at about 50mph, the noise came back. The racket from behind the cluster is loud enough (and I guess vibrates enough) to make the surrounding needles kind of twitchy, too. Since the speedometer is mechanical, I don't even know HOW that's possible.

So does this sound like a typical "you need a new cable / need to lube up your current one" fix, or is this something more serious, like my speedometer head giving up the ghost? Can I catch a break this winter? Ugh!

MBNRA · #2 01-21-2009, 10:20 AM

It's the "you need to lube your cable or get a new one if that doesn't work fix" yes.

#3 01-21-2009, 10:25 AM

Get some thin oil, like air tool oil, unscrew the cable from your speedo and run about an ounce of oil through it. The excess will drain out the other end.

I did that to mine last year when it was making the exact same noise as yours and it hasn't made a peep since.

Zerohour3k · #4 01-21-2009, 10:36 AM

Hmm, the only oil I have available right now is Transmission Fluid type F oil, and PB Blaster. I'm guessing the PB blaster would be a bad choice for this, so would ATF Type F work? Times like this make me really wish that I had a garage to work in, rather than freezing to death in a driveway. =P

Oh well, I needed to pull the cluster anyway. My rheostat has been acting up lately, and I've been meaning to solder the little bugger together.

#5 01-21-2009, 10:38 AM

ATF is fine.

pawoSD · #6 01-21-2009, 11:43 AM

Remember to be careful with that oil pressure line in there!

Zerohour3k · #7 01-21-2009, 01:09 PM

Quote:

Originally Posted by pawoSD

Remember to be careful with that oil pressure line in there!

Thankfully, that hasn't happened to me yet. A neighbor down the street from me, though? He wasn't as lucky, and now has a nice black stain on his tan velour interior.

Brief update, by the way. I took the car out for lunch, since it warmed up a bit today.. plus I was wondering if it would still screech at me. Either this morning's bout of "angry bee syndrome" rattled something loose, or lubed up the cable... because my speedometer is now totally smooth right from the get-go (even in the 0-15mph range!), and hasn't made a sound. The true test will come this afternoon, when I take it back on the highway (and a subsequent one tomorrow morning, when it's freezing out).

Maybe I can get a few drops of ATF in there during the weekend. I just need to find the time to do it.

charmalu · #8 01-21-2009, 04:36 PM

use a 10mm and a 13mm on the oil line at the gauge.

Charlie

280EZRider · #9 01-21-2009, 10:16 PM

Quote:

Originally Posted by ForcedInduction

Get some thin oil, like air tool oil, unscrew the cable from your speedo and run about an ounce of oil through it. The excess will drain out the other end.

I did that to mine last year when it was making the exact same noise as yours and it hasn't made a peep since.

This is a good temporary fix; I too have done it. But the howling will eventually return. The fix is temporary because these cables are not removable from the housings, and they are lubricated with grease (not oil) at the factory. Any thin oil that can find its way down the speedo cable is fine. It won't drain out the other end however, for it has nowhere to go. It will simply set at the lowest point in the cable housing.

Ether · #10 01-21-2009, 10:22 PM

What you describe sounds eerily similar to what I've experienced a few times. In my case once the cabin temperature warms up enough the screeching and needle bobbing stops.

The first time this occurred a few winters ago I removed the dash assembly and was able to recreate the sound by spinning up the Speedo with a drill. So my issue was not the cable. My fix was to apply some lube (I believe I used white lithium grease) to the gears inside the Speedo/Odo.

Fast forward to this winter and the wailing squirrel has returned on cold mornings only to disappear when the cabin warms. This AFTER I just installed a new speedometer cable. So, this weekend I plan on going back in and lubing the gears again.

Your noise may indeed be coming from your cable. I just wanted to share an experience where that was not the cause.

280EZRider · #11 01-21-2009, 11:27 PM

Quote:

Originally Posted by Ether

What you describe sounds eerily similar to what I've experienced a few times. In my case once the cabin temperature warms up enough the screeching and needle bobbing stops.

The first time this occurred a few winters ago I removed the dash assembly and was able to recreate the sound by spinning up the Speedo with a drill. So my issue was not the cable. My fix was to apply some lube (I believe I used white lithium grease) to the gears inside the Speedo/Odo.

Fast forward to this winter and the wailing squirrel has returned on cold mornings only to disappear when the cabin warms. This AFTER I just installed a new speedometer cable. So, this weekend I plan on going back in and lubing the gears again.

Your noise may indeed be coming from your cable. I just wanted to share an experience where that was not the cause.

I also understand the fright of this screeching moment. If the cable isn't the culprit, then the problem lies in the speedometer head and not the plastic gears for the odometer. (There is a special grease for that which is designed to stay on the gears whilst turning, albeit slowly). If you take apart the speedo, you can put graphite oil (liquid not powder) on the head itself. This should remedy the head noise.

Zerohour3k · #12 01-21-2009, 11:52 PM

I'm probably going to have my indy replace the speedo cable first, since it's certainly the cheaper option. I'd do it myself, but it's too cold outside to get any actual work done. While he has the cluster off, I'll have him put a few drops of 3-in-1 oil into the speedomter socket, just as a precaution.

Might was well replace my broken rheostat while I'm at it, too. Thankfully I have a spare, and won't need to blow $80 on one of those.

Squabble · #13 01-22-2009, 06:57 AM

I had/have the same problem here:

Ghost Noise, Screeching Dash, Possessed!

I still haven't gotten around to doing anything about it because it's freezing cold outside and I'm very nervous about doing it as I've never taken out the cluster or seen what the back looks like to refer to if something goes wrong.

Anyone have any pictures of doing this? Do you use some kind of hooks or do you take off the kick panel and push from the back? Is it easy to replace the whole cable or should I just lube it and make it go away?

Zerohour3k · #14 01-22-2009, 07:59 AM

I've taken out many a cluster before. Taking it out isn't really all that hard. All you need to do is remove the kick panel, push the sucker from behind (leaving you enough room to get your hands behind the cluster), and start disconnecting cables. On a W123, most of the connections are kind of idiot-proof, in that they only go in one way / to one location. As a previous poster mentioned, however, make very certain that you resecure and tighten the oil pressure line BEFORE starting the car back up. The pressure line is a mechanical one, and will spray black oil all over your interior if you forget to put it back on. Also, when you get everything plugged back in, find the speedo cable down by your brake pedal, and make sure there isn't too much slack behind the dash. Too much slack can mean a kink, and a kink can mean a broken cable. Trust me, I've been there.

That being said, mine is still doing it when cold, and even though I kind of "expect" it to happen, it still makes me jump a bit when it does. It's supposed to be a whopping 45 degrees out tomorrow, so maybe I'll fix it in the parking lot of my parts supplier during lunch. I think the worst part of this whole thing, is that it utterly ruins my air guitar solo with a sour whine!