Charge Air Cooler – Leak Check
NOTE: The long term integrity of the charge air cooler system is the responsibility of the vehicle and component manufacturers; however, the following symptoms can be checked by any Authorized Repair Location:
Intake Manifold Pressure – Check Install pressure gauge, Part No. ST-1273, to the fitting in the turbocharger outlet. Install another pressure gauge, Part No. ST-1273, in the intake manifold. Operate the engine at rated RPM and load. Record the readings on the two gauges. If the differential pressure is greater than 21 kPa [3 psi], check the charge air cooler for plugging. Clean or replace if necessary.
Intake Manifold Temperature – Check Install a temperature gauge in the intake manifold. Lock the fan drive in the ON mode to prevent erratic test results. This can be done by installing a jumper across the temperature switch or supplying shop air to the fan. Refer to the fan drive manufacturer for lock-up procedure.
NOTE: Some trucks have a manual switch that will lock on the fan.
Operate the engine at rated RPM and load. Record the intake manifold temperature. Measure the ambient temperature at least two feet in front of the vehicle. The maximum temperature differential must not be greater than 25°C [45°F]. If the temperature differential is greater than 25° C [45° F], check the charge air cooler for dirt and debris on the fins, and clean as necessary. If the problem still exists, check the cooler for internal contamination or plugging.
To check the charge air cooler for cracked tubes or header, remove the inlet and outlet hoses from the cooler. Remove the charge air cooler. Using service Tool No. 3824556, install a cap over the outlet side of the cooler. Install a pressure gauge and a shop air supply line to the inlet side of the cooler.
Apply 276 kPa [40 psi] of air pressure to the cooler. If the pressure drop is 35 kPa [5 psi] or less in 15 seconds, the cooler is okay. If the pressure drop is greater than 35 kPa [5 psi] in 15 seconds, the charge air cooler must be repaired or replaced. Refer to the CAC manufacturer for repair instructions.
NOTE: A leak tank can be used to locate the air leak.