Help Diagnose A Problem...

[Rob Thomson 6]

Unusual one this... my car starts to make a high-pitched shriek after it's done a few miles on the motorway at high(ish) speed.

 

This first happened a few weeks ago. I got about 10 miles up the M5 when it started to make a shrieking noise that sounded like a failing bearing - very hard to describe otherwise. I turned round and got home without any probs. I jacked the car up and found that one of the hub-nuts was loose (don't ask). Fixing that sorted out a few other issues like vague steering and a vibration, and I assumed this was the cause of the shrieking too.

 

Then the other night I took it on the motorway for the first time since. This time it took ~30 miles for the problem to appear, but was much much worse than before. I got towed home by the AA. I've jacked it up and been unable to find anything wrong, everything feels fine and all hub-nuts are tight... The weird thing is that I've been out for a spin and the car now seems fine; this is a problem that only manifests itself after prolonged high-speed driving.

 

Only other clue is that it's definitely related to car speed, not engine speed. Dipping the clutch or sticking the car in neutral makes no difference to the noise which is only affected by road speed.

 

I reckon there are two probable causes:

 

1. Wheel bearing that's f***ed as a result of the hub-nut coming loose. But it sounds and feels fine and has no play.

 

2. Driveshaft intermediate bearing. But it's almost brand new.

 

Anyone had anything like this or got any better ideas?

 

Thanks chaps.

[205Rog 0 2 Cars]

I would check the Cambelt tensioner as this sounds exactly like what mine started doing.

[Rob Thomson 6]

Thanks. The noise is definitely related to road speed, not engine speed. Though having said that, French cars being French cars means that I should never jump to conclusions!

 

Keep the ideas coming lads!

[Greg205 0]

So, it only starts making the noise when the car had had time to warm up, fan?

[Anthony 1,003]

Are you still running 1.6 GTi Bendix calipers on the front? Had a similar problem with a friends car, and it was the caliper binding slightly on the disk due to worn sliders, heating up and making a god-awful noise after a few miles at speed. Lightly pressing the brakes would vary the noise, and there was alot of heat thanks to the binding, so should be easy enough to eliminate as a suspect.

 

Otherwise, could be a wheel bearing and the side that had the loose hubnut would be my first suspicion - does the noise vary at all as you turn? I appreciate that corners aren't plentiful on motorways and you don't really want to be swerving around at speed, but does changing lane momentarily alter the noise at all, or does it change on gently left or right handers?

 

Once it has started making the noise, does reducing speed / stopping for a short period make the noise go away again, or is it then present for the rest of the journey?

[GLPoomobile 958]

Maybe the fubar bearing only shrieks when it's getting really hot from the high speed. I dunno, would there be that much of an increase in heat from the motorway speed compared to normal driving?

[steve@cornwall 100]

Maybe the fubar bearing only shrieks when it's getting really hot from the high speed. I dunno, would there be that much of an increase in heat from the motorway speed compared to normal driving?

 

 

anything like this? happened after 50 or so "spirited" miles - been fine ever since. I've long suspected the o/s outer cv was fubar due to the scraping / clicking noises it occasionally made - then this

 

[Rob Thomson 6]

Hello chaps,

 

Are you still running 1.6 GTi Bendix calipers on the front? Had a similar problem with a friends car, and it was the caliper binding slightly on the disk due to worn sliders, heating up and making a god-awful noise after a few miles at speed. Lightly pressing the brakes would vary the noise, and there was alot of heat thanks to the binding, so should be easy enough to eliminate as a suspect.

Yep, it's still running the Bendix calipers, though they are both new (reconditioned). I don't think it's the brakes, I did feel the wheels when I stopped for the first time and there was no unusual heat. The brakes also felt normal, and I think I braked to a standstill and that didn't make any difference.

 

Otherwise, could be a wheel bearing and the side that had the loose hubnut would be my first suspicion - does the noise vary at all as you turn? I appreciate that corners aren't plentiful on motorways and you don't really want to be swerving around at speed, but does changing lane momentarily alter the noise at all, or does it change on gently left or right handers?

I did do a bit of high speed swerving and the noise didn't change. Initially it seems specific to a certain speed, i.e. slowing down or speeding up removes the noise altogether. But very quickly it worsens to the point that the pitch might change a little with speed but the volume barely changes at all. Also, in the early stages it does vary with throttle position, generally being worse under acceleration or engine braking.

 

Once it has started making the noise, does reducing speed / stopping for a short period make the noise go away again, or is it then present for the rest of the journey?

Yep. Initially I stopped at some services for ~10 minutes soon after the sound started. When I carried on there was no further sound for another 10 miles or so (though I was driving more slowly) but then it came back with a vengence

 

Maybe the fubar bearing only shrieks when it's getting really hot from the high speed. I dunno, would there be that much of an increase in heat from the motorway speed compared to normal driving?

Yeah, I reckon the shrieking is due to something getting hotter at a constant 90 on the motorway than it does under normal driving. 'Normal driving' includes thrashing it down the local lanes for an hour at a time with no ill effect.

 

Thanks for your help lads. I'll jack it up again tomorrow to see what I can see, and will then do some more road tests to try to better understand what's going on with the little sod.

 

Cheers, Rob.

[Rob Thomson 6]

anything like this? happened after 50 or so "spirited" miles - been fine ever since. I've long suspected the o/s outer cv was fubar due to the scraping / clicking noises it occasionally made - then this

Yep, very similar to that. Interesting...

 

So you didn't change the CV but it's never done it since? Other than this I don't have any obvious CV issues.

[mat1227 1]

Hi Rob, sorry to resurrect an old thread but just done a search having experienced something identical.

 

How did this get resolved? Did you work out the culprit, as I'm convinced this is exactly what's happening with my car (only happens a fair way into longer, high speed journeys, gets more pronounced from that point in etc etc. then next day no amount of low speed driving will get it to reappear).

 

http://forum.205gtidrivers.com/index.php?showtopic=113487

 

As I say the way you describe your problem it's *exactly* the same as what my car is doing. Any suggestions?

 

Thanks & happy christmas!

 

Mat

[mat1227 1]

AAAhhhh Steve - just watched that video - eeexactly the noise I'm getting. Did it just go away of it's own accord? If mine isn't what should I change to resolve?

 

Thanks!

 

Mat

[steve@cornwall 100]

AAAhhhh Steve - just watched that video - eeexactly the noise I'm getting. Did it just go away of it's own accord? If mine isn't what should I change to resolve?

 

Thanks!

 

Mat

 

Changed the front hub and driveshaft (driveshaft mainly because I knew it was shot anyway) I'm 90% certain that noise was the wheel bearing.

[mat1227 1]

Awesome thanks Steve, appreciate it - glad it sounds less likely to be gearbox (your video was identical to my symptoms). Now I just need to find someone reasonably local to Worthing who can change a wheel bearing before New Year if I cross their palm handsomely with silver... long shot but if anyone knows anyone...?!