One of the most neglected upgrades during an engine build is the cooling system; specifically, the radiator and its supporting components. Factory cooling components, like the radiator, were designed to cool a factory engine’s horsepower output. When the output of that engine is increased the amount of heat that is generated follows.

The radiator is just one of many components of the cooling system that will need to be upgraded. We reached out to some heavy hitters in the industry such as C&R Racing, Lingenfelter Performance, and AFCO to gain some insight on cooling a 4th or 5th-gen LS-powered car.

Every component in a factory cooling system plays a vital role to keeping coolant flowing at operating temperature. Depending on the use of the car and the weather conditions, the temperature can increase at an alarming rate, possibly causing it to overheat. Our goal for this guide is to contribute sources for cooling system components for 4th and 5th-gen LS-powered cars.

Radiators And More With C&R Racing

Most modern OEM radiators are built as single-core units which are made partially out of plastic. These units do a satisfactory job of cooling a factory LS engine. However, many companies recommend upgrading to a single or even a dual-core aluminum crossflow or downflow radiator that is specific to its application. Aluminum as a material has a 25 to 25 percent more efficient cooling capacity than an OEM plastic-core unit.

We had a lot of questions for Paul Hammond, aftermarket representative for C&R Racing. Hammond educated us regarding 4th and 5th-gen LS-powered cars. He says, “There are many factors to consider when selecting a radiator. We’ve found that most enthusiasts have either supercharged or turbocharged vehicles, and the factory radiator and intercooler unfortunately gets in the way, more than it helps.

“For 5th generation LS-powered cars like the Camaro, we have a direct-fit performance-core radiator for the ’10 to ’12 Camaro SS equipped with a LS3 from the factory. That radiator fits in the stock location, allowing it to bolt-in just like a factory unit. With the performance-core design, you have the ability to retain some factory radiator features as well. It’s a 600 horsepower capable radiator, which is our most popular radiator option.”

Hammond elaborates further saying, “With any LS engine producing above 500 horsepower, the vehicle’s engine oil cooler needs to be addressed. The LS engine design uses more oil to cool the engine than other engine designs. If you review some of the other performance-based cars by GM, such as the Corvette and the SS, they all come from the factory with oil coolers. Enthusiasts should highly consider upgrading this component, especially on a forced induction car. Forced induction creates a higher heat load on the engine oil, causing the circulation pattern to differ from a factory LS engine.

“There are several solutions available for engine oil coolers, including our own. Additionally, a power steering cooler should be considered. It’s very possible to boil the power steering fluid during a track day or at an autocross event. It’s not uncommon that enthusiasts upgrade to larger wheels and tires. That places a demand on your steering components, so it’s recommended to upgrade the power-steering cooler. The power-steering cooler can be mounted into your radiator, which is what we recommend. We use our own coolers on our NASCAR and roadrace applications.”

C&R Racing’s inline power steering cooler (PN 41-50000) features an all aluminum constructed unit, which utilizes 1 1/4-inch outlets for OE-like fitment. The inline power steering cooler can also be mounted inside of the radiator.

Hammond also touched on the importance of a good radiator cap, saying, “Upgrading to a pressurized radiator cap would be ideal. The factory cap is only around 13 to 15 pounds. A 21-pound radiator cap will allow the cooling system to increase the boiling point of the fluid. A higher pressure cap in the range of 20 to 30 pounds is more optimal. Especially during track days.”

Keeping Track Of Temperatures With Lingenfelter

Lingenfelter offers a variety of cooling system components, such as radiators, water pumps, and thermostats. From 4th gen F-body cars and 5th gen Camaros, to late model Pontiacs, Corvettes, and the CTS-V.

We spoke with Mike Copeland, engineer for Lingenfelter Performance. We’ve interviewed Copeland in the past when he shared Lingenfelter’s C7 Corvette with us. Copeland says, “Depending on the application, the cooling system components that will need to be upgraded will vary. If power levels are in the 500 range or lower, we would recommend upgrading from an OEM thermostat to a lower temperature thermostat. Above the 600 horsepower range, enthusiasts should highly consider an aftermarket radiator. Additional components such as cooling fans and the water pump often need to be upgraded at this level of power as well. Lingenfelter’s 160-degree thermostat (PN L310045297) is compatible with a variety of GM vehicles, and is a direct drop-in replacement for the factory thermostat. The unit does not need any modifications, and includes a new rubber seal gasket. From GM’s 4.8-liter V8 all the way up to the 6.0-liter V8, this thermostat will be compatible.”

Copeland continues saying, “Heat generated from forced induction and the outside temperature can have a major impact on the performance of the engine as well. The intake air temperature needs a way to stay cool, which means keeping heat from robbing the engine of horsepower. Upgrading to electric single or dual SPAL cooling fans dramatically improves an aftermarket radiator. For enthusiasts that are running a forced induction application and an intercooler setup, be aware that it can increase the entire cooling requirement tenfold. It’s highly recommended to consider an intercooler upgrade if the engine is outputting over 600 horsepower.”

Copeland also explains the importance of a functional thermostat as well. The thermostat not only plays the role of displaying the engine temperature, but it also allows the car to run at a cooler temperature. He says, “The factory thermostat is set to engage the fans at 195 degrees. We offer a 160-degree and 180-degree thermostat choice, which are made specifically for 4th and 5th-gen LS engines. They’re an easy-to-install component and are direct replacements for the OEM unit with no modifications necessary for fitment.” The company also includes all of the necessary seals with its thermostat package.

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Lingenfelter's high-capacity radiator is comprised of aluminum, and is a dual-core construction. The package is compatible with '10 to '14 Camaro SS and ZL1 models which utilize either a turbocharged or supercharged application. The wiring harness included provides the provisions for using a manual relay override controller. This is a time delayed device that allows for the circulation of coolant into the intercooler, which allows the fans to run after shutting the vehicle off. This ultimately reduces heat soak between runs.

Evaluating With AFCO Racing

Jay Miller is the cooling products manager at AFCO Racing. Because Miller has an extensive knowledge surrounding the 4th and 5th-gen LS engines, we asked him when enthusiasts should consider upgrading the cooling system components.

“It’s recommend to upgrade the cooling system once horsepower levels have superseded 450 crank horsepower. Our recommendation would be a dual-core aluminum radiator. It’s also a good idea to evaluate the water pump to ensure it can handle the new radiator’s coolant capacity,” Miller said. He recommends it because as the 4th-gen LS-powered cars came from the factory using low-capacity plastic-tank radiators which had minimal core surface, and are not ideal for a performance-oriented forced induction set-up. AFCO offers solutions for virtually every application available; from drag racing, circle track, road racing, and more. The company offers hundreds of direct-fit radiator solutions for many 5th-gen LS-powered applications, as well as LS swapped applications. These units utilize the factory mounting location, making the swap as easy as installing a factory unit.

Miller also gave us some preventative maintenance tips. He says, “We recommend enthusiasts use GM’s coolant for the new radiator. It’s also a good idea to plumb a vent-type hose from the radiator to release any pressure that could possibly build up. Another option would be to bypass the line through the top of the water pump as well. It is also important to have a proper functioning coolant recovery tank and a sufficient enough sized radiator and fan combination for the power being produced. This will prolong the life of the LS engine and eliminate the engine from overheating.”

Because the F-body world has become a more diverse platform over the years, we prompted Miller about the custom and universal radiators AFCO offers enthusiasts for virtually every F-body application imaginable. Many F-body enthusiasts have dual purpose cars, such as a daily-driven street car which sees strip time on the weekends. In the case of our 4th generation F-body Camaro, we utilized an AFCO double-pass aluminum radiator based on our intended purpose of daily driving and drag racing. Regarding our 5th-gen ZL1 Camaro, we took advantage of an AFCO heat exchanger in order to keep our intake-air-temperature as low as possible, while providing a safe-haven for the entire engine through the included fan module combination. The company also understands the need for a high-performance replacement for every LS application cooling solution, which is why it also offers direct-fit LS swap radiators for early GM vehicles.

Conclusion

We’ve learned that factory components and their performance will begin to decline when forced induction or high horsepower levels are introduced into the mix. Not all radiator modules are engineered for the same purpose or application.

As we mentioned previously, it’s a common misconception that upgrading from a factory radiator to a high-performance unit will be enough when enthusiasts choose a forced induction route. However, after speaking with these three manufacturers it’s quite clear that the cooling system needs to be evaluated as a whole as power increases. When considering the cooling system in its entirety, it’s often the case that components such as the water pump and thermostat should undoubtedly be upgraded at the same time.

Upgrading the cooling system as a whole not only ensures that the engine will perform its best, but it also provides safe haven against the engine overheating, which can cause an extreme amount of damage. It’s also important to note that all three manufacturers agree that the final piece of the puzzle seems to be properly maintaining the cooling system. Using the correct type of coolant, seals, lines, and fittings can go a long way with any high horsepower build and eliminate the possibility of the engine overheating.

Whether you’re in the market for a new radiator or an entire cooling system overhaul the experts at any of the companies we consulted for this article can help enthusiasts get the products they need for the performance they desire.