My 1963 Dart's temp gauge been reading kinda low for some time already. Last week it suddenly went up to high-normal range and then dropped all the way down. Gauge and the regulator seems to be ok as the fuel gauge works fine and the temp needle goes up when wire is grounded. Checked the sender today with a multimeter, at room temp it was about 900 ohms so I think it's gone, right? So what would be the most reliable replacement? I read in another thread that the aftermarket ones often are not. Ebay is offering mostly a Standard #52 and one made by Sorensen. The engine is apparently the original 225 slant six. Living in Spain so I'll have to order one from US, don't want to do that but once and get it right. Further, do the threads need some kind of sealer, like a plumbers thread tape?