Hi, i have got a 2006 renault megane coupe cabriolet. Its makes a loud clinking knocking noise froun underneath every time i accelerate and brake, only when i first accelerate and when i brake as if something is flexing. I have so far wasted £300 replacing both suspension top mounts and also a gearbox mount. ANY ideas? (p.s. renault are currently scraching their heads and have no more ideas)

Niel anderton, August 2010

Some Renaults have a lump of rubber/metal on top of the engine that can rattle. I think it is a harmonic damper of some sort. Seen this twice now. Try loading the engine slightly with an assistant looking in engine bay. Failing that find someone with a 'chassis ear' this is 6 switchable microphones clipped around the noise area to isolate it via headphones. Unfortunately won't fit on drive shafts.

mags, August 2010

c.v. joints are maybe worth a look at

wickham, August 2010

check exhaust rubbers

carl, August 2010