Technical 1959 mercury 312 y-block questions.....

And all these readings are after bringing it up to operating temp and letting it idle for around 45 minutes

 

The question is whether there was a problem to begin with. Was it overheating? My Shop manual sez thermostat "opens at .... 185° - 192° F. fully open at 210° - 212° F."

I ran a 180° for a while and the heater output was not nearly as good in cold weather, a 195° is closer to OEM spec. Seems to run better.

 

Headed out for a drive to see how she does on the road......... I'll let you know what happens.......

 

It wasn't actually overheating...... just running hotter than I would like it to...... I dont run it when it's to cold outside so the heater isn't a major issue for me.....

 

Right, but it seems to me the engineers designed it to run at that temperature, why try to outguess them?