Thermostat Temp?

[vultron81]

I am in the process of replacing a 1992 4.3L V6 4 barrel engine with a new 4.3L Gen+ Vortec longblock. I am reusing all the old accesories including the thermostat housing, water pump, and exhaust manifold/risers. Originally the engine used a 143 degree thermostat. However, the newer motor calls for a 160 degree thermostat. Which thermostat should I use? The boat will be used at an altitude of 4000 ft above sea level and in fresh water only.

 

[Ned L]

Re: Thermostat Temp?

If you will be using the boat in fresh water ONLY you will be fine with the 160? thermostat (this will actually be better for the engine). If you ever go to salt water you will need to drop it back down to the 140?. This is because at the higher temperature the salt will percipitate out of the water and clog the cooling passages inside the engine.

 

[rjlipscomb]

Re: Thermostat Temp?

If you will be using the boat in fresh water ONLY you will be fine with the 160? thermostat (this will actually be better for the engine). If you ever go to salt water you will need to drop it back down to the 140?. This is because at the higher temperature the salt will percipitate out of the water and clog the cooling passages inside the engine.

Ned, can you explain that a little better to me. The salt will precipitate out of the water at higher temperatures or when cooled to lower temperatures?

 

[Ned L]

Re: Thermostat Temp?

Thinking about it, I guess 'percipitate' may not be be the correct term (yes, you can disolve more salt into hot water than cold water). The problem is still the same. A 'raw' water cooled engine in salt water will end up with internal cooling passages plugged with salt if run with a normal temperature range thermostat (180? - 190?). It is necessary to use a 140? max thermostat if running raw water cooled in salt water.