Recovery Tank

A recovery tank is a container attached to a race car's cooling system that catches excess coolant when the engine heats up and returns it to the radiator when the engine cools down, preventing spills on the track.

When a race car engine runs, it generates tremendous heat. The cooling system uses a liquid called coolant to absorb this heat and keep the engine from overheating. As the coolant heats up, it expands and takes up more space, similar to how water expands when it boils. This expansion creates pressure inside the cooling system.

Without a recovery tank, this expanding coolant would simply spray out onto the track through a pressure relief valve. This creates two major problems: it wastes coolant that the engine needs to stay cool, and it makes the track surface slippery and dangerous for other drivers. In fact, most racing organizations require recovery tanks specifically to prevent these hazardous spills.

The recovery tank works through a simple but clever system. It connects to the radiator (the main cooling component) through a hose. When pressure builds up from the hot, expanding coolant, the radiator cap opens a valve and releases coolant into the recovery tank instead of onto the ground. The tank essentially acts as a safe holding area for the extra fluid.

Here's where the "recovery" part comes in: when the engine shuts off or cools down, the coolant contracts and shrinks back to its original volume. This creates a vacuum or suction effect in the cooling system. The radiator cap's valve opens again, but this time it pulls the coolant back from the recovery tank into the radiator, refilling the system automatically.

This overflow tank system keeps the cooling system operating at maximum efficiency. A radiator that's completely full of coolant works better than one that's only partially full or has air pockets inside. Air in the cooling system can cause hot spots, corrosion, and reduced cooling performance.

Recovery tanks are usually made from plastic or aluminum and feature a vented cap on top that allows air to escape but keeps the coolant contained. They're typically mounted somewhere in the engine bay where they can be easily checked and refilled when necessary. A hose extends from the top of the tank down to the bottom inside, which allows the coolant to be drawn back out efficiently.

You'll find coolant recovery tanks on virtually all modern race cars, from professional NASCAR vehicles to amateur track day cars. They're also standard equipment on racing motorcycles, go-karts, and other motorsport vehicles. Beyond racing, the same technology appears in regular street cars, though racing regulations often have stricter requirements about tank size and mounting location to ensure no coolant ever reaches the track surface.