Introduction

Even though we all dream of blasting through the desert at 130-MPH like Robby Gordon, most of our 4×4 adventures take place at a much more reasonable pace. Unfortunately for our engines, crawling along a boulder-strewn dry river bed or climbing a goat trail through a mountain pass does not always allow enough airflow to keep our engines cool with a belt-driven mechanical fan. Belt-driven fans are designed to keep your engine cool when traveling down a street or highway, not while crushing boulders at 3-MPH and 1,500-RPM. So what can we do to keep our rigs from boiling over this summer? Follow along with us as we install a pair of 11-inch electronic cooling fans along with a programmable fan controller, both from SPAL USA.

SPAL Dual 11-Inch Fans

The dual 11-inch fans from SPAL can flow 2,780-cfm of air and will keep a properly equipped 800-horsepower engine cool, so they will work great with most stock and mildly modified 4×4 engines. The dual fan and shroud assembly measures approximately 23.5 inches wide, 16.25 inches high, and 4.25 inches deep. We installed the fans on our 2000 Chevy Tahoe Limited with its mildly modified 5.7-liter Vortec engine. We have driven the big SUV across the country towing a heavily loaded trailer, towed large boats for our sister magazine FAMILY and PERFORMANCE BOATING, and through the deserts of the southwest in 100-plus degree weather. The results: the SPAL fans have kept the engine cool under all operating conditions we have thrown at the rig.

Installation Overview

Including time to pause for photography, the removal of the stock fan/clutch assembly, removal, modification, and reinstallation of the fan shroud, and installation of the electronic fans and controller took about 6-7 hours. If you are mechanically and electronically inclined and plan to perform the installation yourself, give yourself a full day or maybe even a weekend to make sure you can complete the install. If, after reading about the installation on our rig, you do not feel you have the skills required to properly install the fans and controller, have the system installed by your local 4×4 shop. Just be sure to tell them your friends at 4×4 BUILDER sent you.

Modifying the Factory Fan Shroud

Rather than build a custom fan shroud to mate the new SPAL fans to the radiator at this time, we simply modified the factory fan shroud and mounted the SPAL fan assembly to the factory GM shroud. In the future, we will build a custom shroud for the truck and show you how we did it right here in 4×4 BUILDER.

SPAL Fan Controller

The SPAL FAN-PWM fan controller is easy to mount and wire and even easier to program. Measuring in at 4.75 inches high, 2.5 inches wide, and 1.25 inches deep, it is small enough to mount inside the cabin of your 4×4 but weatherproof so that it can be mounted under the hood. We chose to mount the controller along with the FRH Fan Relay Harness on the passenger side fender well between the battery and the air cleaner housing. Be sure to look for an unobstructed area to mount the units in your rig and verify that there are no wires, hoses, or other obstructions behind the panel before drilling any holes or mounting any components.

Programming the Fan Controller

When used with most modern fuel-injected engines, the SPAL fan controller can piggy-back on the factory temperature sender signal to turn the fans on and off. For older vehicles without electronic sensors, SPAL offers the FAN-PWM-TS temperature sensor that can be installed in the cooling system. When the installation is complete, the fan controller will need to be programmed; this is accomplished with the fans unplugged. To program the controller, start the vehicle with the fans unplugged and allow the engine to warm up to the desired low temperature, for example, 160 degrees. When the desired low temperature is reached, press and hold the “Low” button for 3 seconds, and the yellow LED will blink to indicate the low temperature has been programmed. Continue letting the temperature climb until the desired high temperature is reached. When the desired high temperature is reached, press and hold the “High” button for 3 seconds, and the red LED will blink to indicate the high temperature has been programmed. After programming both low and high temperature levels, shut off the engine and allow it to cool before plugging in the fans.

Normal Operation

Under normal operation, when the low temperature is reached, the yellow LED will turn on, and the fan will run at full speed for 1/2 second then begin to run at 50%. Fan speed will increase as engine temperature increases. When the high temperature is reached, the red LED will turn on, and the fan will run at 100%. Additionally, at the high temperature setting, the auxiliary fan will also turn on and run at 100%. When the engine cools to approximately 10 degrees below the high setting, the controller will switch back into low-speed mode, shutting off the auxiliary fan and slowing the primary fan. At approximately 10 degrees below the low setting, the controller will shut off the fan.

Integration with A/C Systems

The SPAL FAN-PWM will also integrate with A/C systems to run the fan(s) at full speed when the A/C system is on. The controller will work with trinary A/C systems to run the fan(s) only when the pressure requires or with standard A/C systems where the fan(s) will run whenever the A/C compressor is on. When properly installed, the green LED will turn on, and the fan(s) will run at full speed whenever the A/C is on.

Cost and Conclusion

With the entire package coming in at just under $450 without the SPAL temperature sender and around $475 with the temperature sender, it isn’t necessarily cheap. But then again, overheating and blowing your engine out on a trail in the middle of nowhere will cost a whole lot more. So if you are as serious about your rig as we are, it may be worth the investment to improve the cooling system by swapping to electronic fans. As a bonus, ditching the belt-driven fan will unleash some additional horsepower from your engine, and which one of us wouldn’t like a little more horsepower?