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Corvette C3 Project Vehicle - Don't Lose Your Cool

This Month, We Upgrade Our C3's Cooling System

Dave Young Nov 1, 2009
Vemp_0911_01_z Corvette_c3_project_vehicle Stock_cooling_system 2/32

Despite what you may have heard, Corvettes don't have to run hot. This month we'll show you how make your car's stock cooling system perform its best, as well as how to modify the system so your engine runs cool on even the hottest summer day.

Because of their design-and specifically the slanted orientation of the radiator-Corvettes have always borne the unfortunate stigma of running warm or even overheating on hot days. While the angled radiator is not ideally designed for maximum cooling, like much of the Corvette it is a compromise between optimal performance and aerodynamic efficiency. In reality, engineers at GM spent considerable time designing the Vette's cooling system, and given the space constraints of the engine, they did a commendable job. Indeed, most Corvette engines will be adequately cooled with the stock cooling system. Add a hot engine or compromise the cooling system's design, however, and you're sure to notice your car's temperature gauge climbing toward the red end of the scale.

Vemp_0911_02_z Corvette_c3_project_vehicle Temperature_gauge 3/32

Keeping a Corvette cool generally isn't a problem so long as the engine is stock, and the factory cooling system components are in good working order. As our cars get older, however, radiators tend to get clogged with corrosion, fan shrouds and seals are damaged or discarded, water pumps lose their efficiency, and thermostats become inclined to stick. And if you've added an engine with more displacement or a higher compression ratio, the factory system may not be adequate at all. With these things in mind, the first step to ensuring your Corvette doesn't run hot is to evaluate the car's cooling-system components as well as its engine and intended use. Only then can you decide whether to restore the original system or make upgrades.

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Driving your Corvette is a blast, but if you're like us, you get nervous when the temperature gauge starts hovering over the 200-degree mark or creeping toward the redline. Our car definitely needed help keeping cool, so we put in a call to Zip Products.

Although our C3 project vehicle was running when we got it, the car's cooling system was in obvious need of some help. While the radiator had been replaced with a factory-style re-cored unit, the fan shroud and engine-driven fan were missing, and two small aftermarket electric fans had been installed. Making matters worse, the radiator and shroud seals had deteriorated to the point of being nonexistent, allowing much of the cooling air to go around the radiator instead of through it. Since our engine is a fairly stock small-block, we decided to initially make the best of our factory components before upgrading to some trick cooling-system components from Zip Products.

Vemp_0911_04_z Corvette_c3_project_vehicle Electric_fan 5/32

One of the first steps we took was to remove the inexpensive aftermarket electric fans installed by a previous owner. In addition to being improperly installed, these fans were wired directly to the alternator lead, creating a potential fire hazard.

Knowing we'd be modifying the existing engine-and eventually swapping to a higher-powered, larger-displacement unit-we decided to purchase the best cooling-system components possible in order to prevent an overheating problem. To that end, we called Zip Products and ordered the company's Direct Fit aluminum radiator with dual electric cooling fans. This setup is available for any Corvette and engine combination, and it bolts directly in place of the stock radiator. In addition to the new radiator, Zip sent a fresh thermostat, hoses, and water pump to ensure our engine stays cool even with the planned future upgrades. Additionally, we ordered a front spoiler to direct more cool air through the radiator. While we waited for our parts to arrive from Zip, we figured we'd service the car's current cooling system so we could do some driving.

Luckily, the radiator in our car was a fairly new piece, and since there weren't any obvious coolant leaks, we directed our attention to the electric fans that were installed by a previous owner. These fans were small, cheap aftermarket units and were barely held in place, so we decided to remove them along with their suspect wiring. Since the previous owner had provided the original fan shroud, we installed it with an engine-driven fan. This cooled our Stingray well enough for normal driving and commuting. Even so, the coolant temperature of our warmed-over 350 would still creep toward the warm side of the gauge while idling in traffic on hot days. Needless to say, we were happy when our new components arrived from Zip.

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When they did, we tore open the packaging and were pleasantly surprised at the quality of the Zip hardware. We quickly got busy removing the factory radiator, shroud, fan, and water pump before installing our new 160-degree thermostat, fresh pump, and front spoiler. The aluminum radiator and fans went in last. The Direct Fit radiator comes pre-assembled with the thermostatically controlled fans in place and all the wiring and relays required to complete the installation. Once installed, the cooling fans work just like those in a new car, automatically coming on when the temperature reaches a certain limit, then shutting off when the engine is sufficiently cooled. Working at a leisurely pace, it took us the better part of a Saturday to complete the installation. The results were well worth it, as our Stingray now runs some 15-20 degrees cooler, even in the hot Florida sun. Follow along and we'll show you how you can attain the same results for your Corvette.

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After unpacking and inspecting our new Zip parts, we drained the C3's cooling system.

Making A Statement
Anyone involved in building performance or collector vehicles will tell you that the cars most revered and remembered are not simply the ones with the best paint, the nicest interior, or the most power. To build a truly unique project car, especially a Corvette, the car needs to be a well-rounded and well-appointed performance vehicle that's built for a specific purpose. Since this is VETTE magazine, and performance is what we love, our C3 will be assembled with an emphasis on speed, adhesion, handling reflexes, and stopping power.

It's been a few months now since we asked you to share your opinions on our C3 project car, and the response has been overwhelming. It seems most of you agree that we should heavily modify the car with some of the best aftermarket suspension, braking, and drivetrain parts available, and that's exactly what we plan to do. Be sure to follow along in future issues as we upgrade the ignition and fuel systems in preparation for a more powerful engine combination. Of course the car will need to stop and handle as well as it accelerates, so there will be plenty of performance upgrades in those areas as well. We've even had a couple of creative engine-swap suggestions, which we'll address later on.

Vemp_0911_10_z Corvette_c3_project_vehicle Aluminum_radiator 11/32

The Direct Fit aluminum radiator comes with dual electric fans already installed. The fans fit nicely and are shrouded to draw the maximum possible amount of cooling air through the radiator.

Speaking of creativity, we also asked for your input on potential project names, an invitation that generated some unique, interesting, and, well, creative responses. While we won't be going with "The Irwin Eliminator" (a joke in very poor taste), "Cool Ray" (not bad), or "Stinky" (we don't even have a response for that one), we did actually consider a moniker from one of our Canadian friends. But although our car will be firmly planted on all four corners, and we plan on having no lack of stump-pulling power, we just couldn't bring ourselves to name our Stingray "Project Moose," no matter how appropriate the title.

These suggestions aside, most readers voiced support for our suggestion of "Project C3 Triple Ex." This title not only implies a tendency toward nastiness, but it also fits the theme of the car, standing for "extreme handling, extreme acceleration, and extreme braking." (Don't tell anyone, but it also pokes a little good-natured fun at another Corvette publication's decal-clad project vehicle.) So with our readers and staff in agreement, our Stingray has officially been dubbed "Project C3 Triple Ex."


Zip Products
Mechanicsville, VA 23111



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