Anybody know much about the mechanical seal? My buddy recently installed a new Esr quick change cover and water had slow drip from weep hole. After starting the bike the drip become excessive! We discovered that he was missing the washer that goes between the seal and the impeller #11 on the oem diagram. Is this part significant enough to make a seal leak or not?? He has the washer on order and new mech seal but we would like to know if the washer alone should fix it before he rips a already new seal out. Does the washer help create a seal when the impeller is tightened down so that coolant can't leak from the center of the seal where the shaft comes through?