Slippy Diff

There is a clicking or knocking noise from near number 2 cylinder ( Impreza Turbo '98 ) which increases in speed as the engine speed increases . It sounds tappety . When I pull of the little connector to unload the cylinder it reduces in loudness and speed but is still there. Can anyone help ? I would like a bit of back up info for when I take it to the dealers and talk warranty claim.

scoobyboy

sounds like the dreaded piston slap to me

Bob Rawle

No 4 for piston slap, sounds a bit more serious, No 2 is the lean cylinder. Could just be a lifter but needs investigating. As another thought, injectors make alot of noise sometimes as well.

Slippy Diff

Piston slap was my first thought but this noise appears all the way from cold to hot. Somebody else mentioned injectors to me. Anyone else want to speculate?

Sieze

Big end bearing failure has to be in the differential diagnosis . Did it come on gradually, or suddenly when slowing from high rpm?

Slippy Diff

It's definitely not a bearing failure , I think !! The noise is constant and is almost certainly not top end.

Slippy Diff

Sorry I meant bottom end!