Cooling Systems Diagnosis
Engine coolant can be checked for antifreeze density with a hydrometer. The gauge on the hydrometer will tell you the freezing point of the antifreeze. The more antifreeze the lower the freezing point. In other words the more antifreeze the colder it has to get for the coolant to freeze.
Use a radiator pressure tester to test for external and internal leaks. Its really nothing more than a pump with a pressure gauge. Install the tester to the neck of the radiator or the coolant reservoir and pump until you reach the pressure marked on the radiator cap. Check around the engine, hoses, and radiator for leaks. Remember to check inside the floor and console area for heater core leaks.
If the engine is started with the tester installed and the gauge quickly increases past the recommended psi. the engine has compression leaking into the coolant jacket. Likewise the coolant can leak into the combustion chamber resulting in a loss of coolant and white smoke emitting from the tailpipe. This is likely due to a blown head gasket. Check for possible causes, remember if you do not repair the underlying cause the head gasket will not last. Aluminum heads tend to warp from heat, cracks can form in the cylinder head or the engine block. Always perform a block test to verify any suspicions.
The tester can also be used to check the radiator cap. There are many different types of adapters depending on the application. Install the cap on the tester and pump to recommended psi. If the cap loses pressure check for old cracked seals and spring pressure. It will be necessary to replace the cap.
Hard to find coolant leaks can be diagnosed using a dye penatrant. Just add the dye to the coolant, heat the engine to operating temperature, and use the black light to go around the usual places looking for a green fluorescent color.
