I learned a long time ago to check those back plate bolts on all water pumps,can't tell you how many times I have found them loose on brand new out of the box pumps. Far as sealers, Peramatex Ultra copper is the only silicone I'll use and only on exhaust applications. I use Permatex RIGHT STUFF on everything else. Stuffs a little pricey but worth it. I use it for gasket sealer,but works very well when you don't have a gasket. Only drawback is it makes things hard to get apart.