Right, after more than two months since waking out of hibernation and trouble free motoring, a small glitch has appeared.

This morning I took the car for a spin. I heard a high pitch tone like the arial caught wind - like a boat's spar in the harbor during a storm. But after pushing the arial back into the fender, the sound stayed.

At first, you hear nothing: when you pull away at a traffic light, all is okay. When you pick up speed, say 25 or so, a rhythmic high pitch can be heard. Rhythmic like a police siren. When you push the throttle: the rhythm stays the same, when lowering the revs (clutch pedal) the sound stays the same. Hence, the 'speed related, not RPM related' title of this thread. I am under the impression that it's coming from the LH back wheel.

When accelerating from 25 to 40, the rhythm gets 'quicker'. Above 45, it's one pitch tone. I have the idea that it is not related to the wheel speed eighter. We all had binding brakes at one point and that pitch & rhythm is road wheel-speed related. I know that sound - it's different from this one.

I was thinking about the fan or belt, but again, that would be revs related, I think.

Any ideas/experience?

Answers on a postcard - or here, please.

Menno

Wheel bearing?
Disc brake?
Tire developed a flatspot from sitting?

Loose muffler hanger ??

Well, that's an idea! I suppose it's not a road wheel / bearing / disc problem since it's not in sync with the wheel speed. I was even considering a lid not being closed properly allowing air to pick up speed when it hits the body of the car. But all's fine on that front.

A loose muffler hanger is perhaps an idea; I will have a look!

What was the cause? I have the same left rear "whistle" that seems to go away while decelerating from the freeway, below 25mph. After adjusting the parking brake, I'm left thinking it is the rear wheel bearing....

Due tell!

Speedo cable?

Could be a wheel bearing, or something rubbing on a rotor. I've had a rock get caught up against a rotor and make a very bad noise.

Wheel bearing was the first thing that came to mind.
Does the sound change at all when cornering? If yes, it's probably a wheel bearing.

Does not change in tone when corner....and I had the same sound prior to me recently removing the rotor and caliper (to replace the rotor).

Perhaps it's the shield rubbing up against the rotor....I'll check that.

Wheel bearings tend to growl, not whistle.

Possibly the speedo cable or angle drive. Can you post a recording?

I'll try to take a video over the next couple days.....can I remove the angle drive and still drive the car to test?

BTW Ian, I watched most of your videos yesterday.....including the front suspension re-bush. Good stuff!!

at least the cable side of the angle drive.....not the entire unit.

Brake dust shield

Quick update....

I removed the speedo cable and took it for a drive.....the sound is still there. Could still be the angle drive if it is still in play with the speedo uncoupled.

I put the car on the lift and looked at all dust shields. The passenger rear was looking a little funky (as the PO dropped the car without a wheel on), but i straitened that out and pushed all dust shields inward a bit for space. Still heard the squeal or whistle sound.

The noise is similar to a brake pad wear indicator, but the rear pads appear new, and I'm not sure 914 pads come with these.

Could it still be the angle drive for the speedo?

(thanks to all that have responded)

Thanks Man!

Sorry I can't be of more help with this issue. You can't pull out the angle drive without dumping gear oil...unless you have some way to seal things off.

Someone mentioned putting the rear wheels on ramps but leaving the front wheels on the ground to keep the rear of the trans high enough to unscrew the angle drive without losing fluid. Seems like a good idea.

Def for changing the gear oil...but he hears this noise while driving so pulling the angle drive to see if the sound goes away would be...messy

So happy for this thread....I have the exact same phenomenon occurring for last two years.....what the f is it? Totally intermittent but drives me crazy.....I figured it is just how engines and transmissions sound....however it does change...but not with any logical shift/unshift/neutral/whatever....what the f is it?
gg

I had a whine that mostly was heard in fourth and fifth gear. Turned out to be a drivers side CV joint that was going bad.

How about jacking rear of car on jack stands and driving car at various speeds and in different gears.

Hopefully that could exclude some of the suggestions made in the thread

If you get it to speed where you can hear it, put it in neutral and shut it off....may help isolate?

Gear oil? Don't chase that. This is a high pitched whistle if I read right.

Had a second thought about this and remembered I had the same problem with my Beetle.

It had not been driven for 3 months and had a high pitched scream coming from the speedo area. The pitch increased with speed. Beetle stuff is fairly simple and I thought the only moving part in that area is the speedo cable. After 10 minutes the sound disappeared. My experienced Beetle friend's explanation was that during the lay up the speedo cable grease had solidified or gotten stiffer and thinned out with use. Not a sound since.

So I would give credit to mepstein and cuddy_k for spotting this earlier in this thread.

Worthwhile disconnecting speedo cable and giving it a run for diagnostics