Aluminum Radiators

Rad-a-Kool Radiator

Thank you for purchasing a Rada-Kool Radiator. To ensure the longevity and optimal performance of your Radiator please read the following instructions.


Your Rad-a-Kool radiator is designed to fit the overall dimensions of the factory mounting location. Most fan shrouds will require modifications. Choose the appropriate height for the radiator position. Be sure when the radiator cap is on the filler neck, the hood can close without contact. If you are using an engine driven fan, be sure the fan blades will not make contact with the lower outlet or hose routing. Mounting flanges must be drilled to match core support mounting locations. The factory mounting bolts can be reused.  


Lubricants must be used when threading into aluminum. Only use a liquid sealant (i.e. Teflon) or light grease for all fittings. Tape sealants can increase the thread size and promote leaks. NPT are sealing threads seal, as well as the seat of an inverted flare fitting; liquid sealants or greases are used solely for lubricating the threads to prevent galling. 

Transmission Cooling Line Orientation

If your Rad-a-Kool is equipped with an automatic transmission cooler, you will find two ¼” NPT bungs located on the cold side (water pump side) of your radiator’s tank. Provided are two ¼”NPT X 5/16” inverted flare fittings for connecting transmission cooler lines.

On the radiator

Top Line, return line:  Returns cooled ATF back to transmission  

Bottom Line, pressure line:  Takes the incoming hot ATF to be cooled 

Coolant Requirements

Always use distilled water, no exceptions. It is strongly recommended to use at least a 50/50 mix of a glycol-based antifreeze and distilled water. A name brand pre-mix is another good option.  


Make sure the engine, chassis, body, and charging system are properly grounded. Inspect for loose, corroded, broken or missing ground straps. Do not use the radiator as a grounding point.

Periodically check the condition of the antifreeze for reserve alkalinity with a test strip. If the coolant becomes acidic, the corrosion inhibitors are no longer able to protect your cooling system from an electrochemical charge (electrolysis) that can eat away at the metal surfaces inside your cooling system. Flush the cooling system thoroughly and replace with new coolant.  

A test for electrolysis can be performed by using a voltmeter or digital multi-meter between the coolant and the battery negative cable. Take one of your readings with the engine off. A second reading, have the engine running at normal operating temperatures. USE EXTREME CAUTION- INJURY CAN OCCUR WHEN CAP IS OPENED. HIGH COOLANT TEMPERATURES WILL BURN YOU.  

Insert the positive lead into the coolant, and negative lead to battery negative post. There are many conflicting readings that have been published as “corrosive level”. The general consensus is .5 volts.  If a current reading is greater than .5 volts, it is recommended to check for proper grounds and coolant condition as mentioned.