metallic ringing sound at partial throttle

[hkwc104]

I've noticed a metallic ringing sound coming from the engine when driving at partial throttle just as the turbo is gently spooling up. It is particularly prominent when gentling accelerating in either 2nd or 3rd gear.

Is this normal or can any one shed any light on what this may be and whether I should be concerned?

Thanks in advance,

Henry

[djpkins]

4 bits that have given me a similar sound...

loose heat shield,
loose hard pipe bracket,
spinning drive shaft seal dust cover,
turbo comp wheel starting to catch on the housing.

all easy enough to get at mate.

[hkwc104]

Thanks mate, will check all of those.

One question though... Where's the spinning drive shaft seal dust cover located and do you know what it looks like?

[cvega666]

The dust covers can be seen in this pic, the rubber boots, check if they don't spin on the shafts also, make sure the bolts on the ring where the 2 half shafts are connected are nice and tight - I had them loose and they made a noise, not quite what you're describing, but a clanky noise.

[Marf]

Ringing?

Definitely doesnt sound like someone rattling a single bolt in a tin can?

[hkwc104]

I would say it's definitely it's a high pitched ringing or whistling sound which is noticeable at lower rpms when driving gently.

If i get a chance this evening, i'll see if I can capture the sound on video.

[djpkins]

The oil seal dust cover is a circular but cupped ring of metal...can be seen right at the end of the drive shaft in the picture, it sits on the drive shaft but can spin loose as it's only held on through "pushfit" tightness....this prob won't be it cos it only rings when the car is in motion.

[ryan]

Id bet its your turbo support bracket. Its probable held in woth one stud and hanging free (the studs shear off).

[hkwc104]

Had a quick check this afternoon and I'm sure its not the hard pipe bracket as it feels solid with no sign of looseness whatsoever.

I also checked the heat shield and that seemed pretty secure too. When trying to move it the only thing that happened was some flex in the heatshield (the end facing the firewall). That said, it does 'tick' after I turn the engine off - is this indicative of it being loose???

Couldn't check if the turbo comp wheel was catching on the housing as I didn't want to take half the engine apart (mainly because I don't know how to or have the mechanical skills to). I also didn't check the drive shaft dust cover given that this is unlikely to be the cause.

[hkwc104]

Had a slightly more thorough check this morning and noticed that I'm missing a couple of bolts and a bracket on my heat shield, so it may be that the heat shield is causing the sound after all.

Does anybody therefore know what:

a) the bolt circled in red connects to? It looks as if someone has cut the top of the bolt off to remove the heat shield possibly due to the bolt seizing/rusting...

b) also whether it's important to have the bracket and bolt circled in blue (both of which are missing)?

[Johnr32]

Im only using 1 bolt on my exhaust heat shield due to one snapping but mine doesnt ring like yours. Try removing the heat shield altogether to see if it changes.

[djpkins]

...not a good idea^^^^^Shonky Re-wire and the Meltoids it's a heat shield for a very good reason.
The red and unmarked secure to the exhaust manifold, the blue one secures to the turbo itself...I doubt very much if you'll be able to drill out the blue one but the other is an easy fix matey. I would make a bracket and find a suitable fixing point for the rear bolt, as opposed to removing the blower to drill it out, it's only the heat shield that needs to be secured against vibes.

[cathalferris]

It's possible that you have a cracked heatshield, that resonates at particular engine loads or rpms. I have this in our '2 but it's a devil to try to resolve without disassembly. I'm tempted to have a go at bridging the crack or adding some foil to the heatsield to change the frequency it resonates at.

[smartdj]

im getting the very same sound you just desribed. i didnt use to have it. its only just started sinse i have my berk downpipe fitted? its a bit weird tbh but it might just be products of conbustions entering the downpipe?

[Skinny81]

does it sound anything like a metallic ticking, my exhaust manifold studs worked loose, the sound of gas escaping made a metallic ping, sounded very mechanical and was hard to pinpoint as sound bounces everywhere in the engine bay.
i pulled the whole bottom end to pieces before i diagnosed it!

[hkwc104]

I'd say it's a metallic sound but not sure I'd describe it as a ticking sound - more of a ringing resonating sound. No harm in checking the exhaust manifold studs so will have a look at those when I get the bolts on the heat shield replaced.