Our Tester-Kit includes rubber plugs starting at 2 ½” [63.5mm] all the way up to 3 ¾” [95.3mm]. Before inserting the rubber plug into the inlet or the outlet of your charge air cooler, make sure that the inlet and outlet are free and clean from any moisture or debris.

Once you have removed the piping from the charge air cooler you can select the appropriate size plug required for your application. Simply match up the plugs from the kit with the connection size, if it's too big take the next one down. Once you find the plug that fits, you’ve found the right size plug. In some cases, the plug available may seem too loose and too small, but don't let that bother you. By tightening a plug that is the closest match, it can be expanded to fit the connection. As an example, a 3 ¾” [95.3mm] plug can be expanded very easily to fit a 4” [101.6mm] connection.

Place one of the appropriate size washers (with oval center slot), rubber plug, second appropriate size washer (round center hole), nylon washer, and tightening handle onto the plug stem with male connector. Tighten the tightening handle to expand the plug just enough to make the plug fit snugly inside hot side (passenger side) connection. Make sure the large washer is positioned flush with the end of the connection and then continue to tighten by hand until the plug feels firmly tightened inside the connection.

When assembling the rubber plug assembly, make sure to always use the nylon washer supplied with the Tester-Kit to reduce the friction when tightening the tightening handle or flange nut and to protect the metal and painted surfaces.

In applications where the tightening handle may not be convenient to use because it can’t be easily tightened, that's not a problem, simply replace the tightening handle with the flange nut supplied in the kit. If using the flange nut with a wrench, be careful not to overtighten.

Place one of the appropriate size washers (with oval center slot), rubber plug, second appropriate size washer (round center hole), nylon washer, and tightening handle onto the plug stem solid. Tighten the tightening handle to expand the plug just enough to make the plug fit snugly inside cold side (driver side) connection. Make sure the large washer is positioned flush with the end of the connection and then continue to tighten by hand until the plug feels firmly tightened inside the connection.

The next step is to use the safety clamps provided in the Tester-Kit. Place the clamps over the tightening handle and then tighten the clamp wing nuts by hand until the notched (“V”) portion of the clamp is snug against the outside of the connection and the large clamp bolts are flush up against the end of the connection of the charge air cooler.

The Tester-Kit gauge assembly is equipped with a pressure relief valve, female quick coupler, and a fill valve (which is the same as the one used to fill your tires) and will be used for filling the cooler with compressed air to perform the test. Connect the gauge assembly female quick coupler to the plug stem with male connector on the hot side (passenger side) of the vehicle and then you are ready to fill with air.

The rule of thumb is to pressure up to 30 psig for most Class 8 applications and watch for a 5 psig drop in 15 seconds. Always refer to Dura-Lite’s Leak Down Rate Specifications chart for the applicable specification to test the engine in your vehicle. 
For the complete and detailed Instructions for using Dura-Lite’s Charge Air Cooler Tester-Kit, refer to the instructions supplied with each Dura-Lite Tester-Kit.

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