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In most cases, when you replace the radiator in your vehicle, the original mounts are reused. U.S. Radiator designs their replacement radiator to accommodate the original mounting style. For custom applications, however, there are options for how you mount the radiator. Even in stock applications, complications may arise where the stock mounts are not suitable for various reasons. Let’s take a look at how radiators are mounted and the differences between them.
Radiator mounts seem like a simple concept, but a good radiator mount is paramount to a long life for the unit. Cars experience lots of different shocks, from engine vibrations to potholes and wrecks. If your radiator is not securely mounted, it can not only break free, but the internal components may be damaged. This is a common issue for modern radiators with plastic tanks. The vibrations lead to stress cracks, which eventually turn into engine-killing leaks or catastrophic failures. Just like your engine, the radiator needs isolation from the chassis to help reduce the shock and vibrations it sees.
Sandwich Clamps
By far, the most common mounting style is a sandwich-clamp, which is a combination of a metal or composite clamp which bolts to the core support over the radiator, with a rubber isolator or grommet between. These are very good mounts and have been used for well over sixty years.
For classic cars, there are usually four grommets, two on top, two on bottom, each capturing the edge of the tank to core weld point, which is the strongest part of the crossflow side-tank radiator. The lower grommets sit in a channel on the lower core support cross rail, while the upper mounts may be individual clamps or one large sheet metal or composite panel. This was very common for most late 1960s through 1980s GM vehicles.
The key to this style of mount is to ensure that the radiator is properly located in the core support with the mounts in their designated locations. If the mounts are in the wrong place such as on the thin edges of the core, the grommets can get cut and they will fail. This allows the radiator to get loose in the mount, and all kinds of bad things can happen. When replacing a radiator, it is always a good idea to replace the grommets with new ones to ensure they are in good condition and will last a long time.
While most grommets are rubber, high-performance polyurethane grommets are available for many muscle cars and trucks. Poly mounts do not break down over time, however some poly mounts have a much higher durometer rating compared to rubber, so they may not absorb as much vibration as rubber grommets, depending on the manufacturer.
Bolt-In Grommets
Many modern vehicles use bolt-in mounts for the radiator with a rubber grommet in the center. The performance is the same: the grommets absorb vibrations and shock and keep the radiator secure. These are two main versions of this style – some are part of the radiator itself, and some are separate mounts that bolt or snap on the radiator and then bolt to the core support.
This type of mount is highly suited for custom applications, as it provides a secure mount with vibration absorption and eliminates the potential for a misplaced grommet.
Non-Isolated Bolt-In
Many early vehicles built up through the 1970s used direct bolt-in mounts to the core support. This is commonly found on early Ford Mustangs, AMCs, Studebakers, and GM trucks up to 1959. These factory hard-mount radiators were all made from copper-brass and are almost exclusively downflow style (top and bottom tank vs. crossflow with side tanks). Because the tanks are on the top and bottom, the mounts are usually on the side of the core.
Many early vehicles built up through the 1970s used direct bolt-in mounts to the core support. This is commonly found on early Ford Mustangs, AMCs, Studebakers, and GM trucks up to 1959. These factory hard-mount radiators were all made from copper-brass and are almost exclusively downflow style (top and bottom tank vs. crossflow with side tanks). Because the tanks are on the top and bottom, the mounts are usually on the side of the core.
All cars twist, especially the older unibody cars like Mustangs and Mopars. In most of these vehicles, the core support is the main body support from the firewall forward, meaning the core support itself can twist and move. If the radiator is hard mounted to the core support, the radiator will twist along with it. This will result in broken tubes. While a stock straight-six Mustang probably won’t see much twisting, any V-8 power certainly will. Full-frame vehicles like full-size Fords and most trucks have rubber body mount bushings between the core support and the frame, which helps reduce the vibrations in the core support for solid-mounted radiators.
If your vehicle has a solid-mount radiator, you have options. You can always fabricate a clamp-mount, but the easiest solution is to use an isolator bushing between the core support and the radiator mounts. The bushings will divorce the radiator from the chassis, providing vibration absorption, and enough isolation from the solid core support to reduce the chances of twisting as the core flexes with the chassis.
Your vehicle’s radiator is crucial to your engine, and how it is secured to the vehicle is just as important. A poorly-mounted radiator is a great way to ensure you will be buying a new one soon. Protect your U.S. Radiator with the best possible mounts and you will much happier down the road. Call U.S. Radiator at 800-421-5975 to discuss your cooling system needs.