Mend > Cars

Noisy Ford Fiesta 1998 1.25cc Engine?

Hi

When I drive my fiesta, each time I change gear and when the engine revs fall slightly into the higher gear, the engine makes a load knocking noise. This only happens when I release pressure from the accelerator.
It also makes this loud noise constantly when driving on the motorway doing a steady speed. The knocking dissappears when I accelerate. It almost sounds like the piston tapping on the side of the engine, becuase the higher the cars revs the higher the freqency of the knocking noise.

I have replaced the oil with a thick 5W-40W, which did help a bit but the knocking is still loud.

Hope you can help.

Dan (Plymouth)
October 2008

Ford Ford Fiesta Vehicles, Cars Ford Fiesta 1998

most likely you've knacked your cambelt and the knocking noise is coming from the cam shaft.... if so i'm afraid it isn't good news and a mechanic might be able to fix it but it will be expensive and thats only if you can find one willing to take it on.....

john babb
November 2008

If it sounds like a piston slapping your in luck it could mean it's 'pinking' which is a weak fuel mixture,if it is a loud knocking noise your big end has gone hence the slight improvement when you put the thicker oil in(which you shouldn't have done)check/enrich the mixture first,or change the engine.

hopefull
October 2008