LEAK TESTING
Some core leaks can be detected by adding water to the radiator. Clean the core so that the damaged area can be found. Refer to figure 9 for a radiator component view.
1. Remove dirt and insects from the fins with a common water hose without a nozzle. Excessive water pressure could damage the fins.
2. Scrub the core with a soft-bristle brush using clean, hot water, or hot water with a mild detergent.
ON-VEHICLE PRESSURE TESTING
Pressure-test the aluminum-plastic radiator with J 24460-01 Cooling System Tester (figure 10). With the system at a cool temperature, remove the radiator cap, connect the gage, and apply normal system operating pressure. Do not exceed 138 kPa (20 psi). Watch the gage needle for an indication of a leak, and examine the radiator and other cooling system parts for escaping coolant.
Repair hose and hose connections as required.
Check the radiator cap to ensure that it will maintain the correct pressure.
If the radiator leaks during the pressure test, mark the leak area.
OFF-VEHICLE LEAK TESTING
NOTICE : Do not use boil-out tanks, vats, or other tanks that have been used for copper and brass radiators . The flux, acid, and caustic cleaners remaining in these tanks will attack the aluminum and cause radiator failure. Use a separate test tank containing clean water for servicing aluminum/plastic radiators.
1. Install test fittings or rubber test caps in the inlet and outlet necks and seal the oil cooler fittings with metal plugs to protect the cooler and keep the fluid from running out (figure 11).
2. Attach the pressure tester and gradually apply air pressure until 138 kPa (20 psi) is attained. Do not exceed 138 kPa (20 psi). Check the pressure gage to see if there is a pressure loss. To ensure that there are no small leaks, run water over the repair area and look for bubbles. (A mild detergent is helpful). If a large water tank is available, sub merge the radiator and check for air bubbles.
REPAIRABLE LEAKS
There are two types of leaks that can be repaired on the aluminum-plastic radiator: core leaks and gasket or seal leaks. Leaks in the plastic tanks cannot be repaired (figure 12).
Core leaks can occur in a tube or in the joints between the tubes and headers. Gasket leaks can occur in the joints between the plastic tanks and the headers or in the joints between the oil cooler fittings and the tank. Some leaks can be repaired while the radiator is on the vehicle; however, it is usually best to
remove the radiator.
REPAIR METHODS
There are several methods that can be used to repair the radiator core, but the hot melt adhesive method repair kit is the most simple and effective. The kit contains adhesive sticks, cotton swabs, a wire brush, and the primer. The adhesive stick is reusable, has an indefinite shelf life, and is waste-free. Store the sticks in a sealed container to keep them dry (figure 13).