Reply to "Proper location for fan control thermostat"

Lots of good opinions and insights. I agree with John to install sensor after radiator. I only want my fans running if the radiator is no longer up to the task of meeting my target temp.

I install my sensor on an extra threaded inlet on my waterpump. That reads the temp of fluid leaving the radiator before being pumped into the block. Depending on the model waterpump you purchased, it may not have an extra threaded input. One may drill and tap another input if proficient.

An alternative approach would be to reverse the flow on your radiator so the already installed sensor bosses are on the outlet side. I don't believe flow direction materially matters on a cooling system with adequate capacity.

I would tune your thermostat and sensor choice to get your oil temps closer to the 220 degree range. My experience running a cooler engine was that I was not getting the oil temp into the 220 degree range. I recognize on these lists that bragging rights seem to go to the owner with the lowest cruise coolant temp. However, cylinder bore wear is more aggressive at these lower temps and power output is increased with oil temps in the 220 degree range. Although, I started with lower temp fan switches and thermostats, paying attention to oil temps has modified my approach raise these temp settings to get back more heat. If you pay attention to oil temps, as the two coolant and oil temps)are related, you may find it beneficial to raise your coolant fan sensor temp and thermostat temp. I use a 195 degree switch because it was the highest I was aware. My oil temps are still to cool.

Summary, monitor your oil temps and adjust from there.