hi there i have done thermostat today the guy who had it must of not done antifreeze for a long time it was like rusty dirty water .. i put whole new thermo on and was great lovely and warm again and some new antifreeze let it sit get warm no problems and hot inside and needle at middle . when i got back i heard water and its coming out near the drain plug not the plug the corner of raditor has rusted and its dripping a lot to a point where its nearly drained again. i can see where its coming from and thinking of using that jb weld metal filler stuff. will this do it and has anyone used it before on this sort of job. ive used it before and know its purposes just wondered if anyone used it like i want to ?