A related point- I have a short jumper hose going from the thermo housing to the water pump, as my heater is not hooked up yet. I have noticed that the engine runs a little warm with that jumper hose in place (as opposed to blocking off the heater hose outlet and inlet).
I surmise that the reason it is running warmer is because the hot water coming up to the top of the block is being directed back into the water pump- bypassing the radiator, which causes the engine to run warmer. Considering the size of the opening in the thermostat and the size of the opening for the heater hose connections, I would say that the quantity of hot water being recirculated into the block, relative to the amount of water flowing through the thermostat, is substantial... Perhaps something to consider when doing your initial start up with no heater connected?
Curious what others think about this, as I have never really considered it before.
Last edited by Norcal Dave; 08/29/2017 3:56 PM.
