Hello my name is Ben and I'm new to this website and forum but I am in search of help finding the problem with my 1991 R32 GTR. Back in October the head blew out a coolant path and had to be removed and welded and fixed so cylinder 6 would not have coolant draining into the cylinder. It worked and was put back on the car with new metal gaskets from a tomei gasket set and a slew of other new parts like a Kevlar greddy timing belt, new water pump, new exhaust guides in the head, all new rubber hoses all over the engine bay(because the others were 28 years old), new mishimoto radiator, new tensioner, tensioner spring, and along with other small things all over the engine bay. During the process of having the head off he cleaned all the throttle bodies which he then found out from someone that builds rb's that he shouldn't have done that(not sure why). When it was all said and done and put back together my mechanic didn't want to give the car back until he looked into a sound coming from the engine bay at idle. It sounds like a whining or whiring sound if you will. It cant be heard when moving but at a stop and idle it can be heard quite loudly in the car and standing outside of it. My mechanic thinks it might have something to do with the throttle bodies being cleaned but is not sure. The car runs and drives great(better then before it broke). He is not positive what the sound is and asked all his other mechanic friends in the area and had them listen to it and they weren't sure or 100% on what it could be either. Just hoping someone could help me out. My initial thoughts are the Kevlar belt making the sound because it is tighter and doesn't have as much give but I'm not sure. Attached is a video of the noise. Clip isnt very long but it gets louder if you rev it up to about 2k and then it quites down a bit. If you have any ideas please help me out.