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Corvette C3 Project Vehicle - Don't Lose Your Cool
This Month, We Upgrade Our C3's Cooling System
Nov 1, 2009
Mechanicsville, VA 23111
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Corvette C3 Project Vehicle - Don't Lose Your Cool
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.
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.
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.
The factory fan shroud is often broken, cracked, or missing from older Corvettes, but luckily the previous owner still had ours and included it with the car. The shroud is a vital part of your Corvette's cooling system, creating a Venturi effect that accelerates air through the radiator for maximum cooling.
Also MIA from many older Corvettes are the radiator shroud seals. We ordered new ones from Zip to seal the shroud, ensuring the cooling air goes through, rather than around, our radiator.
We installed a factory clutch fan temporarily to complete our C3's stock cooling system. The car ran cooler than it had when we first got it, but it still tended to get warm when idling in hot Florida traffic. Needless to say, we were eager to install our new components from Zip products and see what difference they made.
After unpacking and inspecting our new Zip parts, we drained the C3's cooling system.
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.
All of the necessary fittings and hardware are included, even the drain petcock. The radiator also comes with a preinstalled thermostat, which provides a ground to the relays, automatically cycling the fans on and off at predetermined temperatures.
Although aluminum doesn't dissipate heat quite as well as brass, a thicker core and more fins per inch give the Direct Fit aluminum radiator more cooling capacity than a factory unit. Aluminum is lighter as well, shaving weight from the nose of our Stingray.
Since we didn't know the age or condition of our water pump, we ordered a new AC/Delco pump from Zip.
Our Stingray would have come with a 180-degree thermostat originally, but we decided to install a 160-degree unit instead. Remember that the thermostat's temperature rating doesn't determine how warm the car will run, just the point at which it opens and allows coolant to pass through the radiator. The 160-degree unit will give our car's cooling system a 20-degree head start on regulating coolant temperature.
When replacing the radiator, it's always a good idea to install a new cap as well. As cooling pressure increases, so does the temperature at which the coolant will boil. Most factory systems work well with a 15-psi radiator cap like the one we're installing, but for exceptionally warm-running engines, a higher-pressure cap can help prevent the coolant from boiling over.
Rather than taking our chances at the local parts store, we ordered GM molded upper and lower radiator hoses from Zip.
With the new parts delivered, we began the job by stripping our Vette of its radiator, water pump, and hoses.
Before installing the new water pump, we painted it with satin-black engine paint to match the engine and prevent corrosion.
When Zip says its radiator is a direct fit, it means it. Ours slid right in place of the factory unit using stock brackets. New parts that fit this well are a testament to quality manufacturing.
Each fan comes with a relay, a wiring kit, and instructions, making installation easy. Electric components that draw high amperage should always be wired with relays, not directly to the battery or a switch.
We installed our fan relays on the inner fender, inside the engine bay. Although the relays are weather resistant, it's always best to install them in a location that won't be sub-jected to excessive heat or water.
With the fan relays in place, we ran our power wires inside the framerail to the battery compartment, and attached the leads with the supplied inline fuses.
Other than basic hand tools, a set of wire strippers/crimpers is all we needed to install our new cooling-system components.
The power side of the relay is wired to the ignition side of the fuse box, and the ground is routed to the thermostat in the radiator. This setup will automatically cycle the fans on at 195 degrees and off at 175. For more control, a manual switch can also be routed to a ground, allowing the fans to be run at any time.
We reinstalled the coolant-recovery tank that came with our car. This is an important part of the cooling system, as it allows the radiator to recover coolant that is discharged through expansion when the car is hot. If your car isn't so equipped, you can obtain a recovery kit from Zip Products.
Our car has an aftermarket front end and wasn't equipped with a front spoiler. To direct more cooling air into the radiator, we ordered a front spoiler kit from Zip and installed it on our Stingray.
With our new parts installed, we filled the cooling system with Prestone antifreeze/coolant and fired up the car to check for leaks. It's always a good idea to run the engine until the cooling system builds pressure, then check again. Once it's cool enough to safely remove the radiator cap, top off the system with coolant.
In addition to improving the appearance of our Vette's engine bay, our new cooling-system components from Zip lowered coolant temperatures by 15 to 20 degrees. This decrease should improve the car's performance on hot days, and it will undoubtedly come in handy once we start upgrading the engine.
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