[OnTheFence]

Like something is loose. Coming from both sides.
Sounds when rolling slow over bumpy roads. Not drivetrain.

It sounds almost as if its inside the cabin. Rear seat or inside rear doors. Or trunk.
Rear suspension? Sway bar bushings or end links? Loose shocks?

Any ideas?

EDIT:

Solved: E46 BMW ratting rear. Loose top shock mount nut (17mm)

Rattling sound was coming from the rear parcel shelf.
Was not related to acceleration or braking.
Rattling even while coasting at 5mph.
It was a loose top shock bolt (17mm)
I tightened it and the rattling is gone.
When you replace the rear shock, make sure the top cup washer nut is tight.

 

[Galiciae46]

Posibly shock mounts. Have a friend sit on rear seats and listen to that noises.

If they are bad enought it could be visible from the wheel arch.

They are cheap and easy to replace besides they are bad or not.

 

[OnTheFence]

Posibly shock mounts. Have a friend sit on rear seats and listen to that noises.

I replaced the rear shocks, shock mounts, bump stop in 2020.
Think the shock mount top 3 nuts got loose ? Should I check from trunk?

 

[Galiciae46]

If i remember they are selflocking, so maybe not. Recheck.

Since the noise is a rattle it might be easy to determin whats wrong, you need to inspect every link on the rear. Raise the car safely and take a look.

 

[tommy d]

If you live in the rust belt, it might be cracked springs. Usually the first lower wound on the spring will crack and break causing some rattling. Does the car sit slightly lower in the rear and or on one side. It will be hardly noticeable. You have to remove the wheel to fully insect inside the control arm.

 

[TobyB]

What brand shock mounts?

the F'ing Meyle HD's lasted less than 6 months on 2 out of 2 of our cars.

t

 

[Alex323Ci]

i mean it could be so many things from cracked RACP to exhaust. get it up and start tapping things with a rubber mallet.

 

[OnTheFence]

I will jack it up this week and report back

 

[Bali]

Could it be this?

 

[russcoop]

CA huh, your photo? Northeast we done have them but rat snakes can give you a jump

 

[OnTheFence]

Solved: E46 BMW ratting rear. Loose top shock mount nut (17mm)

Rattling sound was coming from the rear parcel shelf.
Was not related to acceleration or braking.
Rattling even while coasting at 5mph.
It was a loose top shock bolt (17mm)
I tightened it and the rattling is gone.
When you replace the rear shock, make sure the top cup washer nut is tight.

 

[MrMCar]

Solved: E46 BMW ratting rear. Loose top shock mount nut (17mm)

Rattling sound was coming from the rear parcel shelf.
Was not related to acceleration or braking.
Rattling even while coasting at 5mph.
It was a loose top shock bolt (17mm)
I tightened it and the rattling is gone.
When you replace the rear shock, make sure the top cup washer nut is tight.

Glad you found/fixed it.
That will EAT a RSM.

 

[Alex323Ci]

Glad you found/fixed it.
That will EAT a RSM.

i was thinking the same.
actually wondered if it got loose by the mount breaking underneath and causing the gap. those shock nuts are locknuts and shouldn’t loosen up.

 

[OnTheFence]

Glad you found/fixed it.
That will EAT a RSM.

Dumb question. What exactly does that center nut do?
It secures the shock mount to the rod, forcing the rod to extend and move with the wheel?