Classic Mustangs have always been plagued with cooling issues. When they were first introduced, their cooling systems were fairly effective, especially the base sticker-price models void of air conditioning and other power accessories. As Mustangs took on heat-creating options, cooling capacity began to suffer significantly. In more recent years, we've found innovative ways to improve classic-Mustang cooling systems with three- and four-row radiators, heavy-duty fans, shrouds, and in more recent times, electric cooling fans.
The beauty of electric cooling fans is efficiency. They don't consume power the way an engine-driven fan does. As the engine revs, a mechanical fan takes more power to turn, depending on its design. Electric fans turn at a constant speed as needed without robbing power and fuel.
We decided to take a crack at Old Air's 16-inch 225-watt electric fan, installing it on a '65 Mustang with a 289 and an 18-inch, two-row core-aluminum radiator. It provides 2,320 cfm of air flow. Installation was easy and performance has been exceptional. Once the fan's thermostat is dialed in, cooling is spot-on. The only problem we encountered was the Mustang's 60-amp alternator's ability to keep up. When an electric cooling fan is installed, we suggest the installation of a 100- to 130-amp alternator to keep the battery fully charged.
Old Air's 16-inch 225-watt...
Old Air's 16-inch 225-watt cooling fan is an easy bolt-on for standard 18-inch Mustang radiators. Ease of installation depends on your radiator's width. The wider the radiator, the more likely it is that you'll have to shim the fan for a perfect fit. An adjustable thermostat controls coolant temperature.
Our 18-inch aftermarket aluminum...
Our 18-inch aftermarket aluminum radiator is wider than the factory version. In this case, we must shim the fan for a proper fit.
First, remove all four radiator-retaining...
First, remove all four radiator-retaining bolts. These are the electric fan's anchor points.
Once the engine-driven cooling...
Once the engine-driven cooling fan is removed and the proper bolts are installed to secure the water pump pulley, we're ready for action. Here, the Old Air fan is lowered into place for a fit check.
Four bolts are installed and...
Four bolts are installed and lightly tightened for the fit check.
During the fitting, the fan...
During the fitting, the fan is checked for rotation and interference issues. It looks as though we're going to need shims (washers) to clear the radiator. They're available at any hardware store.
The fan attachment points...
The fan attachment points are the radiator's four attachment points. Again, inspect fan clearances before running the bolts all the way down.
Fan clearance from the water...
Fan clearance from the water pump pulley should be at least 1 inch.
Shim the Old Air fan between...
Shim the Old Air fan between the fan and radiator for proper positioning. Our installation called for four 1/4-inch shims.
A test light is used to source...
A test light is used to source power. In this application, we're getting power from the "I" terminal on the starter solenoid.
That terminal is live when...
That terminal is live when the ignition switch is on or in the "start" position.
The thermostat's dry-bulb...
The thermostat's dry-bulb sensor is located at the radiator for accurate temperature detection. Begin thermostat adjustment at full on, then gradually turn the knob counter-clockwise until the engine-coolant temperature rises. Drive the vehicle and closely watch the temperature.
Fit And Function
Electric fan performance depends on proper fit and operation. The Old Air fan should be close to the radiator but at least 1 inch from the tubes. If you get too close, air stagnation issues can cause hot spots. Positioning the fan at least 1 inch from the radiator core promotes good air flow and better cooling. To achieve the proper distance, shim the fan at its attachment points. Maintain enough clearance between the water pump pulley and fan to ensure there's no chance of interference.
When searching for a power source for your Old Air electric fan, never get it from the positive terminal at your ignition coil. Because the ignition coil gets its power from resistor wire, it gets approximately 9 volts from the battery instead of 12 volts. If you connect your fan there, your Mustang might stall when the fan comes on. Get your power from the "I" terminal on the starter solenoid. If that doesn't work for your application, source the power from one of the power terminals underdash that's live only when the ignition is on. Always protect your Mustang with a fuse or circuit breaker between the power source and fan.