Back on track: Thermostatic switch for the electric water pump

[Anders Dinsen]

With the corrosion problem professionally fixed by fellow Matra owner Frederik Moes, and the car passed MoT without any comments, I'm ready to work on the Weber conversion again.

As I'm taking the thermostat housing off anyway to fit the extension, I'm also going to fit the electric water pump I have been lying in a box in my basement for more than a year now. This involves a modification to the thermostat housing to accomodate a thermostatic switch to activate the pump, which I have now done:



The switch sensor is pushed through a crush seal in the brass adapter in the bottom of the housing. There's usually a blanking plug there, but I've drilled the hole out and cut a 1/2" BSPT thread to accomodate the adapter.

The pump will be fitted in the lower radiator hose in the front of the car. A relay under the dash will activate it when the thermostatic switch activates. I'll also fit an override switch. The thermostat is adjustable, and I expect that it will take a bit of experiementation to find the correct setting. A more elaborate solution involves discarding the mechanical pump entirely, but that will require a complete redesign of the water cooling system, and I'm leaving that for later!