2004 lb7 with mods in sig, ever since replacing the head gaskets and installing the 66mm turbo I have been chasing a exhaust leak sounding noise, it ticks at idle and fairly loud under light light load. I thought it must have been the downpipe flange so I ordered a new flange and clamp but when I went to replace them I noticed the flange looked fine so I installed the new clamp and went for a test drive, no change at all. Back at the shop me and a buddy went over it with a stethoscope very carefully trying to find the source of the ticking noise, the only thing I noticed is three injectors were louder than the rest and appeared to have diesel leaking slightly around the top....... Just for the anyhow of it I pulled the oil cap and noticed a tinging noise, it sounds like a washer rattling around on a shaft but I have no idea what in a duramax would cause something like that??? Any guesses on either noise?