Coolant flow direction
 

Does water flow from the upper radiator tank into the engine OR is water pumped from the lower radiator tank through the block?


I will need a thermostatic switch to energize an electric puller fan. Recommendation was placing it at the radiator drain petcock but I'm unclear about the plumbing soas the switch has access to max temperature. Methinks adding another separate female fitting for the thermal switch on the radiator tank would be best.

Re: Coolant flow direction
 

It could depend on why you are going electric fan, usually you switch fan on based on need, the return cooled coolant is getting hot(lower tank temperature), if you are trying to use electric fan to make up for other problems with the engine/cooling system perhaps you want the fan to come on earlier/run most of the time, then the sensor in the top hose or top tank of radiator

Re: Coolant flow direction
 

Cooled water is taken into the engine from the bottom of the radiator. If you want to control the fan by engine temperature the switch would need to be exposed to the water expelled from the engine at the top. There are differing thoughts as to which the best place to install the switch.

Re: Coolant flow direction
 

Both.

Re: Coolant flow direction
 

Suspect that you won't need a thermal switch as it will probably be running all the time anyway.

Re: Coolant flow direction
 

It's best IMHO to use pipe plugs in the heads.