172 Knocking

[Goders172]

Hi guys my 172 has developed a rattle/Knocking under the bonnet. When you rev it and let off just as it returns to idle something clatters together for a few seconds. It sounds like its right at the front of the engine bay and can only be heard from outside the car.

Any Ideas??

 

[Goders172]

:bump: :bump:

 

[ben_p]

remove the engine cover.
undo the 4 bolts on the left hand mount
get a bar(big one)
jam it behind the back of the mount and rest it against the strut piller
****mind the AC pipes**** do not rest it against them
push the bar towars the rear of the car (moving the engine forward as far as it will possibly go)
nip all four bolts up nice and tight

 

[ben_p]

if its not that then its the gearbox mount,

the knocking sounds like the exhaust is hitting the subframe

 

[Goders172]

Ill have a go thanks