Stange noise whilst moving

[cdt]

When my car is moving there is a strange noise from behind me towards the fuel tank and boot. It sounds like something repeatedly hitting a pole - like the noise you'd hear from wires against a flagpole but with increased frequency.

I had this noise before but it was intermittent, now I get it whenever the car is moving. The noise continues in neutral and with the clutch disengaged, but goes when stationary.

I have a roll bar, which could be something to do with this. Any ideas?

[leorest]

Something touching the prop or a driveshaft.
They are both about the same construction of a flagpole!
Possibilities include wires, connectors, fuel pipes , handbrake cable, Welsh flags….
Get it up in the air pronto and look for a shinny wear mark in the paint (&or rust) on the drivetrain.
Drive at a fixed/known speed and work out the approximate frequency. You should be able to work out whether the frequency matches road speed or prop rpm.
Best of luck
Leo

[grahamw48]

Exhaust ?

[SEvans]

Could it be the fuel sender arm banging on the side of the tank? Does it stop once the car has stopped moving for a while and the fuel stopped swishing around?

[cdt]

Thanks for the replys.

The noise doesn't seem to alter in frequency based on revs or speed. It does increase in frequency with bad road surfaces.

It stops instantly when the car is stationnary and still is there when braking.

[tallbloke]

Sounds like exhaust pattering on rear suspension or against body work to me. Check your mountings and rubbers. I had a broken bracket on the tailpipe which caused a similar problem this spring.

[Number 7]

Someone trapped in the boot?

How about securing the back end on axle stands, chocking the front wheels and running it in gear? You may be able to see something or tell more accurately where the sound is coming from.

7.

[firefox1712]

Don't move!

[wedgeman]

Have the same on the 400SE from time to time - found to be the exhaust tapping against the chassis at the back.

If you get a few more revs on you can't hear it...

[350zwelgje]

Have an exhaust close to the chassis (don't we all?) sometimes tapping on it. A driveshaft hitting it as well, but the gear stick extension at the back of the box can do it as well by hitting the propshaft (several posts on it in the past) and fixed this on mine.
Did not want to mention broken chassis or broken differential mount, but had to for completeness.

Rob