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Street Race Truck More... The Toolbox

Single Pass, Double Pass, Triple Pass radiators; what’s the difference?


Single Pass radiators allow the flow of coolant to pass through the radiator one time. Double Pass radiators do it twice. Triple Pass, you guessed it, they flow through the radiator three times.

Now that that is covered, we can move on to the cool stuff (pun intended). The job of a radiator is to remove as much heat from the hot coolant as possible. To accomplish this, the coolant passes from the tanks on the ends of the radiator to thin tubes in the radiator. Heat passes from these tubes to the thin aluminum fins that surround them, and then dissipates into the surrounding air.

Single Pass

Single Pass radiators have one channel that goes from inlet to outlet, hence “single pass.” These work well in street applications, as well as some race applications. On these radiators, the inlet and outlet are usually located opposite of each other. The factory water pump on your vehicle should be adequate to move the coolant through without issues.

Double Pass

A Double Pass radiator will have the inlet and outlet on the same side. This is due to the fact that there are two channels the hot coolant will flow through on its path back into the engine. These radiators will work well in both street and race applications as well; however, a high-volume water pump is a recommended upgrade. Since the inlet will be on the opposite side, you may have to divert your upper radiator hose, and you can accomplish this either with a pivoting water neck, or by changing the hose entirely.

Triple Pass

Triple pass radiators are more suited for race applications. Inlets and outlets will usually be on opposite sides again, as the flow will pass through three times. High volume pumps, little to no restriction, and 1-to-1 pulleys are basically a requirement in order to ensure the optimal circulation and cooling effects.

Top any of these choices off with a solid shroud and a good puller type electric fan, and your engine will be running cool for a long time!

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