Help me diagnose this intermittent noise

[skinnyman]

Car is an LS3 R8, manual.

The noise is a metallic grinding/rattling noise, when accelerating, mostly in 1st-3rd gear, more prominent when the engine is cold. It's barely audible in 4th-6th, and is loudest at lower revs, gets more high pitched, but quieter, when travelling through the revs. Some days its very obvious, other days it's barely noticeable, if there at all.

Noise goes away when I come off the throttle/coasting
Doesn't do it when I rev the car in neutral
Sounds like its coming from underneath the car, just infront of the gear lever (though could be the engine bay, it's hard to tell tbh)

Quick google search brings up mostly issues with Nissans, and I've seen explanations ranging from wheel bearing, to gear linkage bushes, to heat shield rattle, to exhaust gaskets, to belt tensioner, to alternator, so I'm at a loss. The car is going to Walkinshaw on Monday for some other work, so I'll mention it then, but was hoping to have a rough idea before it goes in.

So, has anyone on here had a noise that sounds like this? If so, what was it?

I'm hopeful it's a heat shield, but I'm fearful is something gearbox related.

[throwyourbike]

Might be considering normal. The gearboxes are agricultural at best.
I guess it depends on severity of the noise.

Could just be that the gaiter is torn and letting in more noise than normal?

How many miles are on the car?

[snowwolf]

With what you have said, I would guess the gearbox is at fault.

[skinnyman]

Not what I wanted to hear.

With it being when the gearbox is under load, and no noise when cruising, potential for gearbox mount? The car is on 80k and its pretty rusty under there (going for underseal treatment after its been to Walkies)

[snowwolf]

Could also be drive shaft from gearbox to back axle, have heard about mount bearing failing, hopefully that as you could get one from raving or other wreckers, I would think the support bearing on shaft, what makes me think that is a gearbox problem would be there all the time, a bearing on the shaft could come and go with noises, without getting it up on a ramp its going to be hard to pinpoint

Edited by snowwolf on Wednesday 2nd August 19:19

[bigwheel]

Do LS3's have the notorious spigot bearing in the flywheel?

[skinnyman]

I'll stick it on the never ending list of things for Walkies to look at. It's going to be there for week at this rate.

[snowwolf]

The vxr8's don't suffer with the spigot bearing issues, a bigger bearing was fitted to the boxes

bigwheel said:

Do LS3's have the notorious spigot bearing in the flywheel?

[skinnyman]

Interesting development today.

Car was making the noise as usual on the way to work, then off the lights I gave it some WOT, noise instantly gone and didn't return for the rest of the journey.......

[vxr2010]

a heat shield or some thing else loose under the car , a heat shield issue can cause what appears to be a gearbox noise

[Boosted LS1]

Exhaust gaskets?

[Dave3166]

I'm no mechanic by any stretch of the imagination, but, could it be exhaust mounts worn

Perhaps to obvious, but hey, worth a shout....!!!!!!!!

[EssexVXR8]

Have you got a lightened flywheel/ clutch assembly?

[R8heron]

Sounds exactly like what I've had for a few years now, although mines an auto, would only rattle at around 1300rpm in 1st to 3rd up to around 35mph, somtimes on idle or when pulling away or rolling along and also when turning off engine it would rattle just as it stopped.
but mine also did it in neutral which made me think it must have been forward between engine/gearbox and since it sounds rotational like a ball rolling in a metal can noise i thought it must have been the torque converter. I had the gearbox rebuilt and recon the converter, but after a few weeks the noise came back, and so now Ive bought a new converter and flywheel which went on a couple of weeks ago and the noise has since gone

[skinnyman]

Well the car went to Walkinshaw on Monday and they found a multitude of issues with it (as I suspected before hand), some of which were contributing to these noises, such as the knackered wheel bearing and cracked headers.


So it's now having new wheel bearing, Walkies headers/cats, a clutch, exhaust removed and repositioned, and a whole bunch of other things.

With the list and money it's costing I'm hoping it'll feel like a completely different car when I get it back!

[R8heron]

yea I just had a whole load of stuff done also but it was needed and feels and sounds like a different car now, was well worth it but so glad the noise has gone it did my head in so hopefully it works for you too