look at the factory banjo bolts. when the threads stop, and it is smooth to the hex head, it is the same diameter. the metric/an fittings i got, where the threads stopped, it got smaller. so the factory washers(expensive suckers, too. about 4 bucks each) could not center. also, you MUST be aware that it aint gonna leak till the thermostat opens. i think about 180 deg, then, it if aint sealed, WATCH OUT. since i had already made the switch to a bigger cooler and aeroquip lines, the factory banjo bolts were never going on there again. jb weld, end of story.