Re: water temp or water pressure gage whats best
Both would be best. Pressure gauges are more widely used. They can give a false sense of security under some conditions. They read pressure whether it is water pressure or steam pressure. If your motor has a weak or damaged water pump or a leak in the supply line to the engine it might not be able to fill the block completely to the top. If that were to happen the upper cylinders will run hot and any water hitting them could be turned into steam and the pressure will rise. This used to happen on Merc inline 6s, top two cylinder would melt from lack of water and the owner would swear the pressure gauge was reading fine or higher than normal before meltdown. This also happened when the engine was over trimmed or was raised high enough on the transom to interupt a solid supply of water to the inlets.
