What is this sound!

[Macadamia]

I know how difficult it is to diagnose a car sound even when you're there to witness it! But this is pretty distinctive, if anyone has heard it they will recognise it.

It's hard to isolate exactly where the sound is coming from. It's almost certainly outside underneath the car and not something INSIDE the car vibrating. To me it sounds like a heat shield vibrating or even rubbing against the drive shaft but I've been under the car multiple times to check and they're all clear, in place and well secured! Its coming anywhere from the second row seats or further back.

The sound occurs on and off, under all different road conditions, on and off road, different speeds. the most common seems to be going up an incline or in a saddle at the start of the incline. but it's also completely inconsistent. it might happen once on a SLIGHT incline I drive daily and not happen again for a month.

There's no loss of power, can change gears with paddle shift without any hesitation or problem and on the 4x4 screen the centre dif is unlocked. there are no errors. The car is under no stress.

This one that I captured is actually the longest it has ever gone for in a single go. usually it's just a blip and gone. this was on a very slight incline, at about 1200rpm.

[Tombie]

Does it sound like it’s central under the vehicle?

Check the rear shaft centre bearing carrier.

[Plane Fixer]

Check the cat heat shield under the LH side passenger floor. I had that a while ago.

[Briar]

Check the cat heat shield under the LH side passenger floor. I had that a while ago.

Ditto. That exact same thing happened to me once. I had to drive through a a storm and hit some decent puddles on the LHS of the road. The upspraying water hit the heat shield and forced it into contact with exhaust. After I worked out what it was, just bent back into place by hand.

[Eric SDV6SE]

Seems to me heat shield rubbing against exhaust, or on suspension component. Noise seems to coincide with slight rises in the road.

Check heat shields on passenger front wheel well

Another point could be around exhaust where it crosses the transmission pan - you will need to pull the belly pan off. This is a double layered plastic and aluminium pan, dirt and rocks get trapped in between and then rattle. Alu heat shield gets bent up and contacts exhaust crossover pipe.

[HarryO]

Seems to be a series of back to back sounds- To me it sounds like the knobs on the wheel tread rubbing on the wheel arch cover of something similar like that..

[Macadamia]

Does it sound like it’s central under the vehicle?

Check the rear shaft centre bearing carrier.

what am I looking for here? The boot is intact, no splits, no excessive movement and the heatshield isn't deformed and has no wear marks to indicate rubbing.
driveshalf bearings 1.jpgdriveshalf bearings 2.jpgdriveshalf bearings 3.jpg

Check the cat heat shield under the LH side passenger floor. I had that a while ago.

this one looks well secured also.
cat headshield.jpg

Seems to be a series of back to back sounds- To me it sounds like the knobs on the wheel tread rubbing on the wheel arch cover of something similar like that..

I'm on standard 255/55/19 wheels so almost no chance of rubbing and all the arch panels are secure.
wheel arch.jpg

It's got me stumped!

This is the only heatshield that isn't totally secure. I couldn't get the bolt for the compressor guard over it. I'd be surprised if it was this though. I can't even hear the compressor inside the car so doubt I'd hear this. All the same I've zip tied it secure and will see how it goes.

compressor heatsheild.jpg

[Eric SDV6SE]

This is the only heatshield that isn't totally secure. I couldn't get the bolt for the compressor guard over it. I'd be surprised if it was this though. I can't even hear the compressor inside the car so doubt I'd hear this. All the same I've zip tied it secure and will see how it goes.

compressor heatsheild.jpg[/QUOTE]

I think we have a winner there, also check the transmission sump guard in the right of that picture.

[HarryO]

Hi Mac - Did you find it ?

[LuckyLes]

Hi,
I had the fuel filler pipe vibrating against the inner guard a little while ago. took me a while to work out where the noise was coming from. Another time I had a stick get jammed between the heat shield and exhaust.
LuckyLes