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1990 Mustang Project - Thermostatically Controlled Electric Fan Upgrade - Recession Special
Quell Those Rampant Underhood Temperatures Before They Cook Something Valuable.
We all love the sound of a new exhaust system, the thump of a hot camshaft, and the thrust of added torque, but all too often we ignore those sub systems that our hot rods depend on to get from point A to point B. These "other" things include suspension, brakes, and your cooling system. It's this last little detail that we're going to address on our project Recession Special.
The aftermarket makes some great upgrades for your Fox-body Mustang, and they'll definitely get the job done in regard to keeping your Horse cool under the hood. After hearing about a sweet boneyard electric fan upgrade, we had to try it ourselves.
Rumor from a good friend of ours was that the Ford Contour had a great dual-electric fan setup and that it was damn near a drop-in for the Fox-Mustang platform. Electric fans have always been a good upgrade for the Fox-body Mustangs as they work more efficiently than the factory clutch fan setup, and the reduced engine drag usually frees up a few ponies. We like anything that offers up free power, so we got the ball moving.
We called Rusty Acres auto salvage in Jacksonville, Florida, for the lowdown and, according to the sales staff, the dual-electric fan that we wanted was available on all V-6 Contours from 1995 through 2000. Six-cylinder '99-'02 Mercury Cougars and Mystiques also utilize the same fan. Some four-cylinder models did feature the dual-fan, but most were supplied with the single unit.
Our efforts to find concrete technical specifications on the Contour fan have come up short. Internet lore says 3,600 cfm at 30 amps, and we did find an extremely similar fan for sale that offered up 3,400 cfm. All we know is that it takes all of 30-40 seconds for the fan to cool the coolant to its preset temperature. We also have to think that the increased airflow improves the efficiency of our front-mount intercooler as well, at least when it's running.
We've heard of prices as low as $40 for used units from the local pick-n-pull to upwards of $180 for new setups. Rusty Acres normally sells the double fan for $100, which fits our tight budget restraints. As we found out while mocking it up against the radiator in Project Recession Special, it's just about a perfect fit. It's slim, too, and we confirmed with our rumor source that it easily clears an 8- or 10-rib supercharger pulley, even when mounted to a large aftermarket radiator.
When installing an electric fan, it's important to use an electrical relay so you don't tax your charging system too much. Most factory fans pull a lot of amps from the charging system, so we picked up a 40-amp electrical relay form the local auto parts store for six bucks.
If you wire the electric fan to a key-on power source, there's a good chance that your car will never heat up. This can cause a number of problems, not the least of which is frozen occupants in the winter and a computer that never sees closed-loop operation. That being said, we sniffed around the Summit Racing website for a thermostat control and found the Flex-A-Lite PN 31147 temperature control unit. It retails for $26.95 and is just what we need to make sure the engine operates consistently at a given temperature.
For wiring, we used a T-tap connector to pick up the key-on positive signal from the coolant overflow sensor harness and connected that to the key-on source on the temperature control unit. From there, we ran a wire to the 40-amp relay and its switch terminal (86 pin). The relay was then grounded on the 85 pin and a 12-volt constant power source was fitted to the 30 pin. The positive 12-volt output (87 pin) was then connected to the electric fan positive leads.