What a lot of our customers in your situation have done with great success is add the EWP® (part no 8005 or 8030) into the lower radiator hose, wired direct to the battery via an on/off thermal switch (part no 0401) and use the EWP® as an auxiliary pump, while retaining the existing mechanical belt-driven pump.

Both the existing belt-driven mechanical pump and the EWP® will pump through each other when running alone and they will boost each other when ruining at the same time. In fact, when running together they will pump more than the sum of each pumping alone.

You set the temp switch to the temp below which you want the engine to run. If the temp goes above that set temp, the EWP® will turn on and run until the engine temp is 4 degrees c cooler and then switch off.

When the engine is idling the existing belt-driven pump may be producing 15 to 20 l/min coolant flow rate.  The EWP® will kick in with another 80 to 150  l/min.

When you turn off a hot engine, the heat in the exhaust manifold passes to the block and the engine temperature actually increases after you turn off the engine. More heat goes into the side where the exhaust manifold is located. If the head is alloy and the block iron, they will expand at different rates. In any case, the head will tend to twist to accommodate the difference in temperatures, and then the head or the head gasket will be damaged.

If the EWP® is wired direct to the battery, when you turn off a hot engine, the electric water pump will continue to run and wash out heat soak and cool down the engine evenly, until the engine temp reaches the set temp less 4c.  After the EWP® turns off, the heat may still transfer and the electric water pump will turn on for another shorter period. The EWP® may run for about 2 minutes all up and at 6/9 amps there will be very little drain on the battery.

This set up will eliminate heat soak and the engine damage associated with it as well as significantly boost cooling when the engine is running, especially at idle.