I have a 2003 Mitsubishi Carisma that has an annoying slapping noise. It appears to come from around the timing belt region of the engine (drivers side in the UK) and is in time with the revs. There's no problem with starting or running the car, and there's no effect on performance, water temperture or mpg, that I can make out. The garage said there's nothing wrong with the timing belt, and said it sounds electrical, like the engine is sparking across somewhere. Any ideas?

 

is it a ticking? comming from the engine or outside of it

 

It sounds like it comes from the timing belt, though it's difficult to pin dwn the exact location. Others have suggested the water pump, or the alternator. The garage mentioned that the timing belt bearings are worn, but that might be unrelated.