Cooling the 4.6

Modular Article: Cooling your 4.6. by Bob Cardoza

The cooling duties in the stock 4.6L Mustang comes from a 195 degree thermostat and EEC-V controlled cooling fan. In stock configuration the fan won't turn on until around 215 degrees causing the temperature gauge to fluctuate up and down, or worse yet, to run very hot. The gauge usually points to the "m" or "a" on the temp gauge. You can't do much to alleviate this problem without installing an aftermarket chip in the computer. So here is what you can do to solve this quandary without installing a chip.

First, install a 180 degree thermostat (NAPA no.139). The thermostat by itself will not cool the car down significantly but it will take longer for the engine to warm up so you'll know it's working. Next, buy a fan controller from your local auto parts store. I bought a Hayden model 3647 for about $40. It is an adjustable fan controller designed to turn on at the user's setting anywhere between 160 to 210 degrees.

You will have to lengthen the wires on the control box somewhat depending where you mount it. I mounted mine on the fuse box with double sticky tape. Remove the fan, or rather just unbolt it and move it enough to get to the radiator. Included with the fan is a temperature probe you will have to stick in between the coils on the radiator. Be careful to make sure that there will be room for it when you re-install the fan. On the factory cooling fan there are three wires, ground, low speed, and high speed. The middle wire in the bundle is the low speed wire. This is where you will connect the Hayden Fan Controller. Tap the fan controller into this wire using a splice connector. Don't disconnect the factory wire, you can parallel the new wire with it. This way when you turn on the AC the fan will go on automatically and you won't have to splice more wires from the controller to the AC unit. You won't damage the computer, all you are doing is turning on the fan earlier and the fan doesn't care where it gets voltage from.

The controller has provision for "key on power" or you can wire it to run after the engine is turned off. This came in handy when my intake cracked and leaked coolant. Even with the engine off the fan stayed on until the engine was cooled down.

The wiring is pretty simple, just lengthen the wires as needed and mount the control box wherever you want. The temp that the fans come on is controlled by a small control, experiment with it to turn them on when you want. With this setup the car runs right between "o" and "r" on the temp gauge, even in August here in S Fla. The other thing I would recommend is to drain some antifreeze and fill the radiator back up with distilled water and a bottle of water wetter. You want to change the ratio of antifreeze to water from 50-50 to something like 30-70 with the water wetter.

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