Classic Performance Products Installs Dual Fans

1967-72 Chevy truck

By Damon Lee

If one is good, two are better, right? Such logic may not always hold true, but there's something to be said for a pair of electric fans pulling air through your radiator. The folks at Old Air Products certainly think so. They felt a double dose of sucking power was a good solution for hot-running '67-72 Chevy and GMC pickups, so they developed a bolt-in kit specifically for the application.
Actually, you don't need to wait for an overheating problem to benefit from a dual-fan setup like this. For starters, many truck owners prefer electric fans because it doesn't take any horsepower to run 'em. Furthermore, they can be lifesavers in heavy stop-and-go because they don't rely on engine speed to draw large quantities of air through your radiator. The skewed-blade design of the Old Air electric fans allows them to provide approximately 2100 cfm of combined flow for maximum cooling capability.
This particular setup is designed to have one fan running whenever the ignition is on, with the second fan kicking in at a given radiator temperature that you determine. With the addition of a trinary pressure switch (sometimes requiring an adapter), the second fan can be hooked into your OEM or Old Air air conditioning so it will kick on whenever the A/C is running.
We recently watched as Alan Crouse installed an Old Air fan kit on a '71 Chevy belonging to Jim Ries at Classic Performance Products. The whole procedure literally took about an hour. The fan assembly bolts in place using the original fan shroud mounts, and wiring is a simple matter of securing two power wires to the positive battery terminal, routing one to the fuse box, and grounding another. Our particular truck didn't have A/C but hooking the fans into an A/C system should be a straightforward affair as well.

The Old Air dual fan kit is basically ready to install right out of the box. The impressive thing is how self-contained the unit is, with the electrical relays, fusible links, and thermostatic control switch all installed on the fan framework and ready to be hooked up.

Naturally, the installation process began with the removal of the old flex fan and shroud.

Two self-adhesive foam seals are included to create a better vacuum and prevent radiator air bypass. The seals are installed horizontally across the top and bottom of the radiator.

The fan assembly is lowered into place just like a fan shroud. In fact, it bolts to the fan shroud mounts using original hardware.

Wiring is fairly simple, with wire lengths that are correct for stock vehicles and terminal ends already installed. Two power wires connect directly to the positive battery terminal. The third wire in this bundle is for the optional trinary, pressure switch that will link fan operation to the A/C system; it was bundled up and left unconnected for our non-A/C application.

A third power wire is routed through the engine compartment and firewall and connected to a 12-volt "key on" power source on the fuse panel. A ground wire also needs to be secured to a body ground somewhere in the engine compartment.

The second fan is thermostatically controlled, with this probe taking the temperature readings. The probe is easily installed by sliding it through the shroud and between radiator fins.

The thermostat is easily adjusted by starting the engine, waiting for it to reach the desired operating temperature, then turning the thermostat knob counter-clockwise until the second fan engages.

The installation took us about an hour, looks like a factory job, and should keep this Chevy running cool without a problem.

It's always best to have shop and assembly manuals on hand to make sure your installation is correct and to make the project as easy as possible. We recommend factory manuals, available at Greg's Automotive

Classic Performance Products  378 E Orangethorpe Ave.,  Placentia CA 92870  Tech Line 714-522-2000


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