The GMC G3500 radiator is designed to efficiently shed engine heat from GMC’s small van line. The thermostat, the radiator, and the water pump all work in conjunction to keep the engine operating at the optimal temperature, which is achieved by maintaining the coolant fluid at approximately 200 degrees Fahrenheit. The radiator of the GMC G3500, like most mass-produced automobile radiators, is essentially a system of aluminum tubes with hundreds of thin, flat aluminum plates or fins attached along their coiled length.

The cooling fluid, ideally a combination of antifreeze and distilled water, flows through the tubes. Heat is conducted through the metal of the tubes to the aluminum fins, where airflow dissipates the heat.

The thermostat controls flow to the radiator. When the coolant is cold, the radiator is bypassed and the coolant flows back to the engine to be heated again.

Once the coolant reaches a sufficient temperature, the thermostat opens, and coolant is free to flow into the radiator. Constant opening and closing of the thermostat aperture keeps the temperature within the optimum range. Like all radiators, the GMC G3500 radiator must be maintained properly to be effective. Rocks, leaves, and other debris can catch between the fins, impeding airflow. Flying road debris, such as rocks or pieces of tires, can bend and damage the fins as well. A few bent fins are unlikely to impede the function of the radiator; however, if large areas of the radiator exhibit damaged and bent fins, it may be prudent to replace the entire radiator.The radiator of the GMC G3500 is well-protected by the grille and bumper area, so it is unlikely to sustain significant damage from normal driving.