Rattle under car

[surrealjam]

Hi people

I seem to be having an issue with a rattling sound which occurs from around 2,500rpm to 3,000rpm.

It is a 'tinny' sound so I presumed it was the exhaust. Having got someone to look into this, they discovered I was missing a rubber mount and replaced it. However, this did not fix the issue...

I am told the exhaust itself is fine - securely mounted but with enough free play. This leads me to think it must be something else.

I realise this is all a bit vague but was wondering if anyone can throw some ideas at me. It definitely sounds 'frontish' so within the engine compartment is most likely.

All suggestions welcome!

Cheers

[Cerberus]

Your cat has broken up internally? Roll under there and give it
a whallop and listen for rattles.

C

[prodjsxb]

Ohhhh, maybe that is what is wrong with my car. I could not find the source of this metal vibration sound that shows up only at a certain RPM

Did that since I bought it, but it passed MOT

[hailesmail]

I had this until I replaced the exhaust back and middle sections. It wasn't the cat as I still have the original fitted.

[surrealjam]

Hi guys

thanks for the responses. My car is a 1990 model and as such has no cat

While the car was up on the ramps, the guy gave it a good few whallops and assured me all was fine. It certainly didn't give off any rattles when simply knocked around.

The guy before me had not long had most of the exhaust replaced and it definitely all looks in good shape.

We both agreed the sound was from the front of the vehicle - as I said, I am now thinking it is more from within the engine bay.

[glasgowjim]

at cerain frequencies the nosecone can give a vibration whaich sounds worse than it is just tighten up he 3 bolts on he top of the nose cone hey will be a bit lose if this is he problem.

[felyx]

check the heat shields near the rear axle , the 2 rubbers on the back box become saggy , if you don't want to replace them use some beefy 5mm zip/cable ties to squish back into stiffness

( i some times this on new rubbers too)

you can also stiffin up the mid exaughst by bending the 2 hooks on the chasis of the car away a little with some big molegrips or swanneck pliers
i would do this with the rubbers on etc.

also check you engine stabiliser on the left hand side of the engine if this is shot it can cause all sorts of noises


cheers felyx

[surrealjam]

Thanks for the comments. I got under the bonnet and had a quick mooch around.

Giving the exhaust manifold a good tap with a solid object reveals a slightly rattley tone though the manifold itself seems fairly solid. Heat shields behind the manifold all seem to fine but is another possibility. I shall check more thoroughly at some other time and report back if I find anything.

I've been warned though - this may be something I never really find!

[LIP]

Hi
Towards the back of the wing, behind the plastic inner wheel lining is i think it's a plastic fixing or metal fixing that hooks into the body work from inside the wing, this sometimes breaks or rusts through & if it does it can make a rattle when driving, jack up the car & look underneath.
it can also be a worn bush that can rattle or make sure the shock bushes aren't loose or worn, I know the rear bilstein shocks don't quite seat in properly & actually rattle around.
hope this helps
lip

[blackbelt1990]

The heatshield on my CAT was loose once, rattled like mad until it flew off on the motorway!

[Raffadakis]

The heatshield on my CAT was loose once, rattled like mad until it flew off on the motorway!

haha (sorry off topic)