jpitman2

There are no free lunches, but if you spend enough time driving in clear traffic, the electric fans will be running much less of the time, and overall consume less power than a constantly running mechanical fan, and hopefully maintain a more steady engine temp. Also, if the electric fan blades are better suited to the rpm used, they should be more efficient than a mechanical one.
As I have remarked above, a top hose sensor will give much better results than the std one at the bottom.
jp 83 Euro S AT 52k

Imo000

I have my Hayden fan's power off the jumper post and at most, it will run 1 min after engine shut down.

Imo000

I have an aftermarket non adjustable temperature switch going throught the fins of the core, right at the point where the hot coolant enters the radiator. The power from this goes into a standard relay. Both the sensor and the relay are power off the jumper post so they have constant +12V, even when the engine is shut down. It should reduce heat soak.

dr bob

The deal with the factory mechanical fan is that the thermo fluid coupling loads the fan only when needed. In that case it's based on air temps behind the radiator, so it's a one big and two small steps away from where the gauge reads circulating temps. It's not engaged all the time. Mechanically it uses less power to get the same work done. It's not necessarily the correct work either way.

It would be great to have a fan controller or coupling that's as smart as the thermostat.