Mystery Noise

[nigelbrooks]

Apologies, as I posted this originally in the 'General' section by mistake.

 

Any help with this one would be appreciated.

 

My 2000 TDi SE Auto Alhambra (47,000 on the clock) has developed a strange metallic 'pinging' noise (happens just once each time as if something is releasing).

 

The puzzling thing is that it happens at 20-22mph and is not related to revs but speed.

 

Have tried pulling off in all (auto) gears, revving while in park no noise until the car hits 20-22 mph.

 

Noise has been there for about ten days, is not getting any louder or more frequent.

 

It seems to come from the front o/s.

 

Handling and performance are unaffected but it is just b***** annoying.

 

Any advice would be much appreciated.

 

Thanks

[HJT]

Very odd. This seems to have stumped everyone :( So when the noise occurs, and you then stop, (i.e traffic lights) will it happen again as you drive off or does it only happen once when you first drive the car? Could be driveshaft or CV joint related? It's not one I've heard of before.

Any suggestions guys?

 

Howard

[nigelbrooks]

Sorry for the delay in getting back on topic.

 

The noise happens every time I hit 20-22 mph.

 

It's really odd. Doesn't happen in reverse (had to find a nice quiet bit of road where I could reverse at speed).

 

Handling and performance are unaffected (have had some fast motorway runs and a lot of urban driving over the past week).

 

ANY suggestions would be much appreciated.

[Guest MATT]

Ime stumped,

 

as HJT has said, it must be something to do with the drive train, as it is only speed related, i really don't know. is there anything on the TIS CD?

 

MATT

[Guest smudge.g]

I have a similiar problem with my 96 Gal. Everytime I get to around 2000 revs, there's a metalic 'rattling' which disappears as quickly as it came. Havent had time to investigate but I think it could be something to do with the exhaust (resonant frequency @ 2000 revs????) as it seems to come from below the floor and around the back of the engine bay.

hope this helps!!

GS

[Andrew T]

Rev related is likely to be an exhaust heat shield.

[seatkid]

The clips that hold the exhaust shields are prone to rust away, so the shields then flap about and rattle.

[Guest j_mchattie]

Are there any systems that initiate at 20 mph? I dont have a Gal, so i dont know. But my Dads landrover has ABS which self tests once upto speed. Might be an actuator for that.

[nigelbrooks]

I have a similiar problem with my 96 Gal. Everytime I get to around 2000 revs, there's a metalic 'rattling' which disappears as quickly as it came. Havent had time to investigate but I think it could be something to do with the exhaust (resonant frequency @ 2000 revs????) as it seems to come from below the floor and around the back of the engine bay.

hope this helps!!

GS

Sadly, it's not rev related.

 

I can 'hold' at say 1000-1200 revs and creep (literally) up to 20-22 mph and then; click.

 

Alternatively, I can floor the throttle and race (well, it's all relative in a TDi) with revs well above 3000 and nothing until....20-22mph!

 

Not worrying, just annoying.

[Guest MATT]

you don't think it is the speedo, do you?

 

how loud is it?

 

MATT

[nigelbrooks]

Matt

 

The noise definitely comes from under the o/side of the car.

 

Not very loud (how do you describe loud?) sort of a "plink" metallic noise that sounds like something 'releasing'.

[Guest marcusheawood]

...Is something catching the disc guard, has it been bent?

[soptom]

I can't help, but offer sympathies, That noise would end up being the only damn thing I would hear EVERY time I drove it if it was my car.

Let us know when you finally sort it. ;)

[nigelbrooks]

I can't help, but offer sympathies, That noise would end up being the only damn thing I would hear EVERY time I drove it if it was my car.

Let us know when you finally sort it. B)

Cheers

 

Im going to check the disc guards this evening.

 

Silly, but all I now listen for is the bl**dy annoying '22 mph plink' every time that I drive the car.

 

Even got my son paranoid about it :D .

 

Still it's a good way to get a 'Kevin' of a teenager actually communicating with his dad "I heard that noise again" is more preferable than the nomal monosyllabic grunt.

[nigelbrooks]

...Is something catching the disc guard, has it been bent?

A meticulous inspection of everything that I can see, wobble, grab and shake, prod etc. reveals, absolutely nothing!

 

Disc shields are fine, nothing appears loose, no tell-tale signs of anything rubbing (bright or unusually 'clean' areas) all hoses and pipes are nicely clipped into place.

 

I'm stumped! B)