I am working on a 97 riv vin1 and it has a chirp/etch noise coming from the front cover area. have replaced timing chain,gears,waterpump,all belt pulleys,alternator,supercharger,p/* pump and it is still there. now only noisy at idle and noise is still there with belts taken off the engine. soundsw like an "erp-erp" from engine. pinpointed to front with stethoscope. need help fast, it is a customers vehicle and it just came back after 6 months. the only way it did go away was when i added BG brand MOA to engine oil after oil change. HELP HELP!Thanks.