Flex-A-Lite - Chevy Corvette Radiator Electric Fan Install

Flex A Lite Chevy Corvette Electric Fan Combination Kit

Flex-a-lite’s new radiator/electric fan combination comes with everything you need to install it in your C3 Corvette (or Camaro) except for new hoses. “When we make a kit, it’s designed to be complete,” explains Lisa Chissus, president and owner of Flex-A-Lite. “We don’t want you to get headaches from it.”

Cooling system woes are as old as hot rodding itself. Any time you build more horsepower, the byproduct is more heat. In recent years, the problem has gotten more acute. Street cars with 700, 800, or even more horsepower are becoming commonplace and these giant numbers necessitate a cooling system just as powerful.

But you don't need horsepower like this to over-burden a cooling system on a classic car. Many of our favorites from the '50s and '60s had cooling systems that were barely marginal from the factory. If you've increased the horsepower of your factory powerplant by 50-percent or more—something that's pretty easy to do with a head and cam swap—you could be at the limit of the factory cooling system's capabilities when it was new. That radiator in your car is probably not exactly as functional today as it was 40 years ago, either.

Then there is the proliferation of aftermarket air conditioning systems for classic automobiles. These are great for keeping passengers comfortable, but was your factory cooling system designed to accommodate the extra heat they throw off? Probably not. For every degree the air conditioning system is taking from the cockpit, it is moving it right to the condenser sitting in front of the radiator. Something else to note: R-134A A/C systems are not as efficient as the old R-12 systems were, therefore they work harder and produce more heat to cool the cockpit the same as R-12. This makes more heat at the condenser and it's blowing right into the radiator.

When we put a 383 stroker in Project Homewrecker, our '72 Corvette project, we had the radiator professionally cleaned by a radiator shop. Everything was hunky-dory until the car and its owner moved to the west coast of Florida from the northeast. This really put the old system to the test. What we noticed at first was in the summer, when temps could be in the mid-90s with 80- or 90-percent humidity, the Stingray would run hotter on the highway than it did in town by about 20 degrees. Not optimal, but we were still in the safe range. Still, this was a sure sign the cooling system was not efficient enough and causing us concern.

The real trouble came after we installed the great C3-specific A/C kit from Vintage Air. While the unit did a remarkable job of keeping the passengers comfortable, the factory radiator and clutch fan was overmatched. At 70-75 mph in the summer on the highway, the orange needle was swinging right near the 250-degree red zone on the temp gauge. Once you got off the road and onto city streets the temp would come down—again, a sure sign the system was overwhelmed—but once parked and shut off, the radiator would puke coolant all over the ground, something it never did before. (This car was never equipped with an overflow/expansion tank.)

Corvettes of this vintage have always run hotter than other Bow Ties because styling took precedent over function. They were the first factory bottom breathers. They take in air from under the bumper, not through the grilles. The chin spoiler was not only a functional aerodynamic piece, but it was also tasked with directing air to the radiator. There's very little underhood area on these early C3s, which exacerbates the problem. Big-block cars were known to overheat in traffic when new.

1. At right is the electric fan controller and attached temperature probe for the radiator. You can adjust the fan to come on whenever you want between 160 and 240 degrees. Flex-a-lite provides the correct grade wire, in-line fuse and every bit of hardware you could possibly need to install the unit.
1. At right is the electric fan controller and attached temperature probe for the radiator
2. The first order of business is to drain the radiator, then remove the upper and lower radiator hoses. Once you’ve done that, unbolt the factory clutch fan and set it in the swap meet pile. The instructions recommend removing the hood before you do anything else, but we jumped the gun a little. Ditching the hood definitely makes things easier when it comes to installing the new radiator fan/combo.
2. The first order of business is to drain the radiator, then remove the upper and lower r
3. The factory shroud is actually two pieces. We found it easier to remove if we separated them. This gives you a little more wiggle room (literally), which came in handy.
3. The factory shroud is actually two pieces. We found it easier to remove if we separated

4. The bottom of the shroud on our ’72 LT-1 Vette rests on the crossmember. This meant we had to pry it up and help it move forward a little for removal. On either side, it is held on with tangs. You’ll have to move it off them as well.
4. The bottom of the shroud on our ’72 LT-1 Vette rests on the crossmember. This meant we
5. It’s easier to remove if you rotate the passenger side of the shroud up about 90 degrees. The good thing about Corvette parts is that restorers are always looking for correct pieces. That means there’s always value attached so don’t throw anything away.
5. It’s easier to remove if you rotate the passenger side of the shroud up about 90 degree
6. A half-inch wrench made quick work of the bolts holding the radiator to the surround.

7. Instead of scratching out marks with a scribe, we used the infinitely more practical painters tape to mark the location of our hinges before we unbolted the hood. This makes reassembly easier with no permanent evidence it was ever off.
7. Instead of scratching out marks with a scribe, we used the infinitely more practical pa
8. Tampa office associates Marc Christ (left) and Justin Cesler removed the radiator from its cradles.
8. Tampa office associates Marc Christ (left) and Justin Cesler removed the radiator from
9. There are apparently two types of mounts for the radiator. Some Vettes (like our example) have two cradles with rubber bushings, while others (possibly earlier ’68-69 models) use male ends (shown above on the Flex-a-lite radiator) that go into holes at the base of the surround.
9. There are apparently two types of mounts for the radiator. Some Vettes (like our exampl

9a. We took a wire brush to our cradles, hit them with some Rustoleum black paint, then reinstalled the rubber mounting bushings. Yes, we should have taken a wire brush to the entire chassis. Don’t remind us.
9a. We took a wire brush to our cradles, hit them with some Rustoleum black paint, then r
10. The radiator/fan combo is a rather slick piece of equipment. It’s a two-row radiator with one-inch cores and the fan moves 3,300 cfm of air, but that’s not the whole story. The side tanks are a patented design that help dissipate even more heat. The whole thing arrives fully assembled, just as you see it. The patented T-channel side tracks are super strong and accommodate the company’s T-bolt brackets. This makes mounting the brackets, expansion tank, etc., as easy as possible. The unit is also a lot lighter than the stocker radiator, shroud and clutch fan. Any time you can remove weight from the nose it’s a good thing. Getting rid of the clutch fan will free up some ponies, too.
10. The radiator/fan combo is a rather slick piece of equipment. It’s a two-row radiator w
11. Marc and Justin carefully placed the new radiator combo in the Corvette’s cradles and Marc zip tied it in place. This allows you to walk around, grab a cold drink and get whatever bolts and tools you need without the radiator moving.
11. Marc and Justin carefully placed the new radiator combo in the Corvette’s cradles and

The thermostat on our project was working fine. We flushed the radiator with a name brand cleaner, installed new coolant with an additive guaranteed to lower temps by up to 20 degrees. No good. We tried a 160-degree thermostat. Still NG. It was simply more than our old girl could handle in the tropical summers it was subjected to. It was at this point that replacing the factory radiator was considered mandatory.

Our trouble became your gain: Super Chevy is able to bring you the exclusive install and test of Flex-a-lite's newest offering, a radiator/electric fan combination designed exclusively for 1968-'82 Corvettes. Flex-a-lite really needs no introduction at this point—it's been in business for 50 years and enthusiasts have been using its fans, radiators, etc., for generations. In recent years, it has been releasing a number of different radiator/electric fan combos for different applications, including '67-69 Camaros and '81-'92 F-bodies. There's even a setup for the current 2010-up Camaro and on the way are Chevelle systems.

There are many benefits to these systems. Yes, they function far better than stock, they're aesthetically pleasing and by ditching the power-robbing clutch fan, you are freeing up 8-10 hp. On top of all this, they come pre-assembled. All you have to do it remove the old cooling system, bolt the Flex-a-lite combo in the factory location, wire it up and you're done. It was remarkably simple and straightforward. We accomplished it one evening after work in our shop, despite stopping for photos, note-taking and a dinner break. We had the benefit of a two-post lift, but it's nothing that can't be handled by anyone in his garage or driveway.

The range of Corvettes are covered by two part numbers, one for the '68-'72 (PN 52180, which we used) and the other for '73-'82 (PN 42181). The former has a side outlet for the lower radiator hose, the latter a front outlet. Our Flex-a-fit radiator is manufactured in the U.S. with a two-row, 1-inch tube all-aluminum core that's hand welded to the side tanks with patented "T" channels to dissipate heat more efficiently. The Flex-a-lite electric fan (PN 180) moves 3,300 cfm of airflow. The radiator can be purchased without the fan if you'd like the former, but not the latter.

For automatic-transmission cars, an optional direct-fit transmission cooler kit mounts a Flex-a-lite Translife cooler to the front of the new radiator. Radiator mounting brackets are included for direct bolt-in fit to the stock location, and the "T" channels provide a more secure attachment for these mounting brackets.

12. Spacers for the sway bar are included for a reason: The bottom of the shroud interferes with the sway bar, prohibiting the radiator from falling completely into the cradles.
12. Spacers for the sway bar are included for a reason: The bottom of the shroud interfere
13. We unbolted the sway bar on both sides and added the spacers. This lowers it out of the way so there’s no interference. Flex-A-Lite supplies the correct length bolts to attach the sway bar.
13. We unbolted the sway bar on both sides and added the spacers. This lowers it out of th
14. Now we have all the space we need (far left) by the sway bar and the radiator combo slid perfectly into the cradles.
14. Now we have all the space we need (far left) by the sway bar and the radiator combo sl

14a. Now we have all the space we need (far left) by the sway bar and the radiator combo slid perfectly into the cradles.
14a. Now we have all the space we need (far left) by the sway bar and the radiator combo s
15. These are the T-bolts on the mounting brackets. You simply slide the T-bolts into the T-channel on the side of the radiator and tighten them. But we’re not ready to fully wang ’em down yet.
15. These are the T-bolts on the mounting brackets. You simply slide the T-bolts into the
16. It’s now time to fasten the radiator to the core support with the supplied bolts. Once the radiator is fully attached, you can tighten the T-bolts. Note: Flex-a-lite supplies foam insulators to mount between the radiator and the core support, but there was no touching in our application so we didn’t need them.
16. It’s now time to fasten the radiator to the core support with the supplied bolts. Once

17. Marc puts the finishing touches to the passenger side bolt. Some cars—ours included—require a different lower radiator hose. We improvised, but Flex-a-lite recommends Eckler’s PN 20469.
17. Marc puts the finishing touches to the passenger side bolt. Some cars—ours included—re
18. Now it’s time for the electrical side of the install. First, insert the temperature probe into the radiator. The best location is put it in the path of the coolant near the upper radiator hose inlet—typically 2-3 inches from the top of the radiator 2-3 inches from the side.
18. Now it’s time for the electrical side of the install. First, insert the temperature pr
19. Then it’s time to mount the fan controller. It needs to be no more than 18-inches from the radiator. We mounted it to the T-channels on the side of the radiator, but learned later this is a bad idea. The heat could cause the unit to fail over time. We’re moving it to the driver’s side inner fender.
19. Then it’s time to mount the fan controller. It needs to be no more than 18-inches from

20. You must attach a spade connector to the fan power feed wire. This will attach to the controller. Whatever you do, don’t attach the power feed to the alternator.
20. You must attach a spade connector to the fan power feed wire. This will attach to the
21. The controller requires a constant 12-volt power source. Optimally, the power feed should be mounted to the battery, but we hooked it up to the battery junction block on the driver’s side inner fender.
21. The controller requires a constant 12-volt power source. Optimally, the power feed sho
22. After that, we attached the spade connector to the appropriate place on the controller. There are only a few wires that go to the controller, but the provided wiring diagram is quite clear and easy to understand for inexperienced enthusiasts.
22. After that, we attached the spade connector to the appropriate place on the controller

23. Next we connected the wiring from the controller to the electric fan. Blue is positive; the black wire is negative.
23. Next we connected the wiring from the controller to the electric fan. Blue is positive
24. When it came time to fill the radiator, we added a bottle of Flex-a-lite’s Flex-A-Chill coolant additive. It’s engineered to prevent scale and blockage, reduce engine temps and extend the life of your cooling system components. We then added about a half a gallon of anti-freeze and filled it the rest of the way with water.
24. When it came time to fill the radiator, we added a bottle of Flex-a-lite’s Flex-A-Chil
25. Here’s the radiator/fan combo installed in the car. We set the controller to come on at 180 degrees. The green wire you see runs from the controller and was spliced into the air conditioning compressor’s clutch circuit. This turns the electric fan on automatically any time the compressor is on. The results have been impressive to say the least. Now, the coolant temp on the high stays in the 170- to 180-degree range, even with the A/C cranking in the tropical summer heat.
25. Here’s the radiator/fan combo installed in the car. We set the controller to come on a