OK, so did my intercooler yesterday. Big smiles. Long job getting it just right, but got there in the end with all the pipes fitting just right... Took it out for a blast, boost hose comes off with a bang. Tickled it back home and put hose back on. Reconnected and tested on idle. All good. Took it out, drove about a mile or so tickling along, and then started to give it a bit of boost. Was fine, all hoses seemed to be OK. So I flat it in 2nd. Rattle rattle rattle..... OK, so stop on the side of the road, engine ticking over, and is still making a metallic clanking sound (almost like an engine with no oil in it - all noise coming from the top end). No EML. Have to drive it home. On the way home, notice that noise is rev related - i.e. more revs, more noise created. Got home, checked spark plugs tight. Yes. Removed TB to check nothing inside. All good. Have also noticed that there appears to be a blowing from what I can only guess is the exhaust manifold, and I think I can smell exhaust gas from the back of the engines.... Anyone got any ideas? Why would a blowing exhaust manifold gasket cause a tapping? It idles fine, and drives OK (well, not being hurt obviously - didn't want to risk it). One word. Arse . Nice shiny intercooler. Car no worky.