Rattle when cruising at low revs

[Girvo]

Hi all,

As mentioned, I'm getting a rattle from somewhere under the wagon, around the middle, if I'm sitting under about 1700rpm. It stops completely over 1700.

The only mods done are a catback that was on there when I bought the car a few weeks ago. I'm hoping it's just something to do with that, but I can't get it on to a hoist for a week or so.

Has anyone experienced this? I just hit 125k km.

Thanks!

[black_friday]

What engine & gearbox? Is it doing it in any particular gear/speed? Can you hear it outside the car or just inside?

[Girvo]

L98/T56. All gears and speeds. Only consistent is low rpm. I can hear it outside with all the windows down.

[ralcool]

I'd check the exhaust & heat shields.

One loose bolt can make all kinds of funny sounds. I had one on a cat converter that came loose several times.

[Micks]

+1 on zorst, cat substrate internals can loosen up & make noises too!

[whitels1ss]

+1 on zorst, cat substrate internals can loosen up & make noises too!

Loose cat substrate will normally rattle on every cold start.

I recently had one that was so noisy on a cold start that
the very first time I heard the noise for the first second I thought it sounded like a chain.

[Girvo]

Thanks gents! Will get her up on the jack this weekend and check everything out.