| Chilling Out – Keeping A Big Horsepower Engine Running Cool
Our Toyota FJ40 is nearing the end of its test mule life. After thirteen years of change, it’s time we settle on a solution and stick with it. After all, I just want to wheel this thing and enjoy it now. But, we wanted to do some radical things to it first, which is why we’re calling its latest incarnation “Extreme Makeover – 4X4 Edition”. If you’ve been following our progress, you’ll know that it has gone through some serious changes such as a stretched wheel base, a 4-link suspension, interior changes and a new 425 horsepower, fuel-injected 383 stroker engine. We’ve been very happy with the progress, but with the added horsepower the engine was running far too hot for our likings. Even with the all-aluminum BeCool radiator and Flex-A-Lite Black Magic fan, the engine was peaking at 250 degrees – that just wouldn’t do.
We needed to take some drastic measures, so we started making calls to some engine building shops to get the low down. Long story short, we needed a radiator with more surface area to keep the monster mill in check. We put our next call into the cooling experts at Flex-A-Lite and told them about our cooling conundrum. I gave them engine bay measurements along with our engine specifications and temperatures and they suggested their highly-efficient Flex-A-Fit cross flow radiator and their Black Magic Xtreme electric fan with an assurance that it would avail us of our over-heating hindrance.
 Flex-A-Fit cross-flow radiators are a revolutionary breakthrough in radiator design, incorporating both function and form. They are constructed of all aluminum and are made with 2-row cores and 1” tubes, making them both lightweight and efficient. The radiator tanks in a Flex-A-Fit radiator are designed with cooling fins inside the tank that act as heat sinks to absorb heat more quickly, then radiate it through external fins that increase the tank’s radiant surface area threefold – some 234% more efficient. Adding innovation to form, the external fins offer nearly limitless fastening points onto the tanks them self, transforming the radiator into a giant, convenient bracket for mounting point, attaching expansion tanks, electric fans, oil coolers, and more. Flex-A-Lite radiators can be purchased separately or included with the Flex-a-lite electric fans which cover 100% of the core. Bottom line, you get a super efficient radiator that is a piece of cake to install and its makes your engine compartment far neater and more organized.
 Our cooling kit came with a Flex-A-Fit cross flow radiator (part # 52180L) that has a 22″, two-row core measuring 27-3/4″ x 18-1/2″ x 7″ overall. It also came with a Black Magic Xtreme electric fan (part # 180) which covers 100% of the radiator’s core and is capable of pushing 3,300 CFM of air through the radiator. The Black Magic Xtreme 180 is the most powerful single electric fan available and boasts a rugged 1-piece nylon shroud, a bracket system that mounts to the radiator (not through it), and has an adjustable thermostat allowing the fan should come on automatically when the engine reaches a pre-set temperature.
We also ordered up a few other goodies such as a zinc anode radiator plug (part # 32060) which save the radiator from corrosion and a very slick chrome overflow tank (part # 32017) which measures 17” long and holds 24 ounces of fluid too.
| Installation - Flex-A-Fit Radiator and Black Magic Xtreme Fan |
| Time: |
5 hours |
| Tools Needed: |
Wrenches, sockets, ratchet, screwdrivers, jack, catch-pan, wire strippers, wire crimpers, paper-towels / rags. |
| Difficulty: |
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Installation
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  We started our installation by disconnecting the battery and then draining and removing the old radiator/fan unit. Our particular installation required some modifications to the body and fender wells as we mounted a very large radiator into an otherwise small engine bay. We also fabricated some mounting brackets that would secure the radiator to our shock hoops. We built an over-the-engine truss to keep the shock hoops from flexing and placed rubber isolators into the mounting brackets to keep the radiator from being pinched if we took a big jolt. Most other installations won’t require this much fabrication.
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 We then test-fit the radiator into place and made some final body and mounting adjustments ensuring adequate clearance and air flow.
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   We removed the radiator and then mounted the adjustable thermostat to the fan shroud using the supplied screws. We also inserted the thermostat probe into the radiator core and mounted the fan back to the radiator.
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  Next, we removed the petcock valve and installed the zinc anode into the radiator.
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 With the radiator fully assembled, we mounted it into our FJ40 and wired it up using the supplied wires and connectors. We also installed an override switch that would allow us to turn the fan on or off manually, which works in conjunction with the thermostat.
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 Next, we installed the overflow tank using the supplied brackets and hooked up the tubing.
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We then added 50/50 anti-freeze and distilled water to the radiator and burped it accordingly to ensure we didn’t have any air pockets.
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 Lastly, we fired up the engine, checked for leaks and adjusted the thermostat so that the fan would kick on at about 175 degrees (to match our engine’s thermostat).
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4x4Review Off Road Magazine
Prior to swapping out our old performance radiator, our engine would reach 250 degrees or higher when idling – not a good situation for a rather expensive engine. With the new Flex-A-Fit all-aluminum, cross-flow radiator and its innovative cooling fins, coupled with the Black Magic Xtreme electric fan, our engine now reaches a steady temperature of 198 degrees, even when idling on the hottest of days. 
