elm,

Leaks happen...try to find it if you can. It could be a loose clamp or loose pipe fitting. A cold engine under pressure, before the thermostat opens would be the prime candidate for a 'little dripper'. Even a head gasket could do it. If it is a leak that can't be stopped by re-gasketing or tightening, then a sealer is not a sin! A tiny can of Alum-seal certainly won't bring the sky crashing down.

I would stick with the 160&deg thermostat, but I would drill a small hole in the flange near the edge. This probably won't hurt anything and might give the coolant a little cushion and keep it from hitting the cold radiator when the thermostat does open.

Stuart