Knocking noise even when car is turned off

[Moh]

Yesterday my car started making a knocking noise which initially sounded like it was coming from the front passenger side wheel. However this morning I drove the car to work again started knocking after it had warmed up.. I then parked up in the car park turned the car off however the knocking still continued only now it's sounds like it's coming from the rear of the car.

Anyone else experienced this? Does anyone know what it is?
It has been raining cats and dogs last night could this have caused it?

[Toms306]

Knocking with the engine off and stationary?

I cant think of anything that could cause that! Unless waters dripping somewhere and echo'ing I guess...but that really is a long shot lol.

[Moh]

Hmm that's what I thought water stuck somewhere and trying to find a way out but the noise is more like when you bend/wobble a metal sheet (stupid example) doesn't seem like it's coming from the engine.

[Toms306]

How often is the knock? Is it regular or random? Does it keep happening when stopped or stop soon after?

[cully]

slaken off the fuel filler cap and try again
tank maynot be venting

[Strikeforce]

Sure its not the exhaust cooling down?

[daveylennon93]

Yeah sounds like its the exhaust "poppin" while coolin down.

[Moh]

The knocking stopped but unfortunately wasn't able to pin point the exact problem

Loosen and closed fuel cap the last night and left the car .. today the knocking stopped

I cannot say for definite that it was the fuel cap as I didn't drive the car immediately after loosening and tightening it so it could have been anything. Thanks for the advice lads