The cooling system in a C2 Corvette has plenty of faults, even in the original configuration, and when you start modifying the engine the problems only get worse. The constant struggle to stay cool has created anxiety in thousands of Corvette owners, as one eye is always glued on the temperature gauge. The subject in this cooling system overhaul is a small-block car backed by a manual transmission and 4.11 gears. The healthy small-block and low rearend gears made for big fun, but anything over 55 mph for more than a few minutes resulted in overheating issues. A five-speed transmission helped matters tremendously by bringing the cruising rpm down, but it didn’t completely reduce the temperature anxiety. A generic aluminum radiator and electric fan also seemed to help, but it didn’t fit the car well enough to be considered a permanent solution.
The car’s previous cooling system eliminated the original expansion tank system. While the universal aluminum radiator was simple and effective, it was a little too tall for the car, making the hood clearance too close for comfort. The radiator hose placement also wasn’t ideal and it just didn’t have the right look. In an effort to cool this low-geared hot rod Corvette, we decided to start from scratch with a new radiator from DeWitts, a new fiberglass fan shroud from J&D Corvette and a box full of cooling system goodies from Zip Corvette.
Going from cobbled together universal parts to a selection of direct-fit parts made for an easy install. It was more work to undo the universal components than it was to install the new pieces. Everything fit as advertised and the assembly process was simply a matter of bolting factory-type pieces together, a task that we handled over the course of a few evenings in the shop. The improved stock-look aluminum radiator and flex fan is certainly capable of cooling this modified small-block, as we have been pleased to see the temperature gauge staying at 180 degrees. In addition to the improved cooling capabilities, the new components cleaned up the engine bay nicely. Take a look at our cooling system overhaul and use the tips and tricks to keep your C2 cool, whether it’s on the highway, sitting in traffic or blasting down your favorite backroad. Vette
1. When our 1964 Corvette coupe rolled into the garage it had a functional cooling system, but the generic aluminum radiator didn’t offer proper fitment. It was physically too tall for the car and the hose outlets were not quite right.
2. The original fan shroud was in pretty bad shape before the universal-fit radiator was installed, but you can see where modifications were necessary to accommodate the radiator hose outlets.
3. After draining the fluids and undoing the less-than-desirable cooling system repairs, we were ready to remove the generic radiator, electric fan and hacked-up shroud.
4. Since our new DeWitts radiator is a direct-fit piece, we whipped out the Zip Corvette catalog for some standard replacement parts. First up was a pair of new radiator cushions (PN WS-333) that fit into the original lower radiator mounts.
5. The radiator is DeWitts’ HP Series (PN 1249063M), which features all-aluminum construction and two rows of 1.25-inch tubes and offers 25 percent more cooling capacity than stock replacement radiators. We ordered ours in the “Black Ice” coating for an original look. The original-style dowels fit nicely into the new rubber cushions.
6. We grabbed a new radiator and shroud center bracket (PN M-259) from Zip, along with a new upper cushion (PN WS-436). We slid the cushion over the original-style tab on the radiator and then loosely installed the two bolts to hold the radiator upright.
7. It would seem natural to install the fan shroud next, but we found that installing the lower radiator hose is much easier without the shroud in the way. The radiator hoses came from RockAuto.com, but you can get them at many Corvette parts suppliers.
8. Now we can lower the J&D Corvette fiberglass fan shroud into place. Before installation, we sanded it and applied two coats of semi-gloss black paint to match the rest of the engine bay.
9. After getting it dropped into place, we installed bolts and nuts in the factory positions. Make note that the original steel shroud had built-in nuts, while our J&D Corvette replacement does not, meaning that it requires pass-through bolts and attaches with nuts and washers.
10. We tightened the side mounting bolts and then tightened the radiator and shroud center bracket bolts. That allowed us to accurately drill the hole for the only remaining fastener. After it is drilled, we install the bolt, nut and washers.
11. Final adjustments can be made to align the center bracket and then the bolts can be tightened.
12. Our six-blade flex fan can be re-installed using the existing hardware. We removed the electric fan, as the new cooling system is more than adequate for this modified Corvette.
13. Any time the cooling system is taken apart it’s a good time to replace the thermostat. It’s cheap and easy to install since you’ve already drained the coolant. We went with a 180-degree thermostat.
14. Our upper radiator hose was a little long so we trimmed it with tin snips until the fitment was perfect.
15. With the upper radiator hose installed—and the dust and our fingerprints wiped off—the new DeWitts radiator and J&D Corvette fan shroud look like factory fresh pieces.
16. Now it’s time to move onto the expansion tank. Since our previous radiator did not use an expansion tank we had removed the mounting straps and bracket. We got a new bracket (PN M-235A) from Zip Corvette and attached it to the inner fender using new bolts.
17. Next are the expansion tank straps (PN M-235). The straps are not pre-bent so we did some trial and error fitment to get an idea of the correct shape. After getting them dialed in, we attached the lower portion of the straps to the bracket.
18. The new DeWitts expansion tank (PN 421) is an exact reproduction of the original Harrison tank. We still had to do some final tweaking on the straps, and then installed the new strap bolts from Zip.
19. Another cheap and easy step for a cooling system overhaul is installing new heater hoses. You can buy the hose in bulk at the local parts store or you can buy the correct stamped hoses from any Corvette parts supplier. We opted for the parts store hoses and installed them with new clamps.
20. Another piece from the Zip Corvette catalog is this heater hose T-fitting (PN M-207). It connects the upper heater core hose to the expansion tank and allows free coolant flow from the water pump.
21. One last trip to the parts store yielded us some new heater hose fittings for the water pump and the intake manifold. We coated the threads with pipe sealant before threading them into place.
22. Although it is rather bulky, this 90-degree fitting is a much better piece than some of the chrome-plated aftermarket versions. We removed the valve cover to give us a little more room to tighten the fitting.
23. We spun the fitting until it was facing the front of the car and then trimmed the heater hose for a nice fit. Next, we trimmed and installed the lower heater hose.
24. Finally, we installed 3/8-inch hose from the expansion tank to the radiator, as well as a 3/8-inch overflow hose.
25. With a combination of parts from DeWitts, J&D Corvette and Zip Corvette, we completely overhauled this Corvette’s cooling system and gave it a super clean look. The final step was pouring a fresh mixture of coolant and water into the expansion tank and taking it for a spin … and 180 degrees never looked so good!
Photography by Tommy Lee Byrd