B5.9G, B5.9LPG – Troubleshooting and Repair Manual – 010-027   Charge-Air Cooler

If the engine experiences a turbocharger failure or any other occasion where oil or debris is put into the CAC, the CAC must be cleaned.

Remove the CAC from the vehicle. Refer to the vehicle manufacturer’s instructions.

WARNING  When using solvents, acids, or alkaline materials for cleaning, follow the manufacturer’s recommendations for use. Wear goggles and protective clothing to avoid personal injury.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause bodily injury.

CAUTION  If internal debris can not be removed, scrap the CAC.

CAUTION  Do not use caustic cleaners to clean the CAC. Damage to the CAC can result.

Flush the CAC internally with solvent in the opposite direction of normal airflow. Shake the CAC, and lightly tap on the end tanks with a rubber mallet to dislodge trapped debris. Continue flushing until all debris or oil is removed.

Use a flashlight and mirror to inspect the CAC for internal debris.

WARNING  Wear appropriate eye and face protection when using compressed air. Flying debris and dirt can cause bodily injury.

CAUTION  The charge air cooler (CAC) must be rinsed and dried, and free of solvent, oil, and debris or engine damage will result.

After the CAC has been thoroughly cleaned of all oil and debris with solvent, wash the CAC internally with hot, soapy water to remove the remaining solvent. Rinse thoroughly with clean water.

Blow compressed air into the CAC in the opposite direction of normal airflow until the CAC is dry internally.

If the engine experiences a turbocharger failure or any other occasion where oil or debris is put into the charge air cooler, the charge air cooler must be cleaned.

Remove the charge air cooler from the vehicle. Refer to the vehicle manfacturer’s instructions.

Inspect the charge air cooler for cracks, holes, or damage.

Inspect the tubes, fins, and welds for tears, breaks, or other damage.

Refer to Section A for the leak check procedure.

Pressure Gauge, Part No. ST-1273

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.

WARNING  To avoid possible injury from either plug blowing off during the test, secure the safety chains on the test plugs to any convenient capscrew on the radiator assembly. This test must be performed with securely fastened safety chains.

Charge-Air-Cooler (CAC) Test Kit, Part No. 3824556

Install a cap over the outlet side of the charge air cooler (CAC). Install a pressure gauge, air supply, and air pressure regulator to the inlet side of the cooler.

Apply 207 kPa [30 psi] of air pressure to the charge air cooler (CAC). Close the air pressure regulator.

Monitor the pressure gauge and determine the rate of pressure decay with a stopwatch.

If the pressure decay is 49 kPa [7 psi] or less in 15 seconds, the cooler is okay. If the pressure drop is greater than 49 kPa [7 psi] in 15 seconds, check all connections again.

Determine if the pressure decay is caused by a leak in the charge air cooler (CAC) or from a leaky connection. Use a spray bottle filled with soapy water applied to all hose connections, and watch for bubbles to appear at the location of the leak.

If the pressure decay is caused by a leaky connection, repair the connection and repeat the test. If the leak is within the CAC, repeat the test to verify the accuracy of the pressure decay measurement. Similar pressure decay readings must be obtained at least three consecutive tests before the reading can be considered accurate.

If the pressure drop is greater than 49 kPa [7 psi] in 15 seconds, the CAC must be replaced.

Refer to the OEM service manual for replacement instructions.

NOTE: Charge air coolers (CAC) are not designed to be 100-percent leak-free. If the pressure decay is less than 49 kPa [7 psi] in 15 seconds, then the CAC does not need to be replaced.

CAUTION  Debris trapped in the charge air cooler, if not cleaned, will cause internal engine damage.

The charge air cooler must be cleaned following any turbocharger or air cleaner malfunction.

Inspect the charge air cooler (CAC) fins for obstructions to airflow. Remove obstructions such as a winterfront or debris. Manually lock shutters in the open position, if equipped.

Lock the fan drive in the ON mode to prevent erratic test results. This can be done by installing a jumper wire across the temperature switch.

Fluke Digital Thermometer, Part No. 3822666

Install fluke digital thermometer, Part No. 3822666, and thermocouple wire kit, Part No. 3822988, into the intake manifold at the 1/8-inch NPT tap near the air horn connection with the intake manifold.

Another alternative would be to use the monitor mode on the INSITE™ service tool.

Install another thermocouple at the air cleaner inlet to measure ambient air temperature.

Perform a road test with the engine at peak power and a vehicle speed of 48 kph [30 mph] or greater.

Record the intake manifold temperature and the ambient air temperature.

Calculate the differential temperature:

Intake manifold temperature – ambient air temperature = differential temperature.

Maximum differential temperature = 28°C [82°F].

If the temperature differential is greater than the specifications, check the charge air cooler (CAC) for dirt and debris on the fins and clean as necessary. If the problem still exists, check the charge air cooler (CAC) for debris in the fins or between the charge air cooler (CAC) and radiator. Confirm full-fan engagement.