[old_master]

Electrolysis can cause pin holes in the radiator and heater core in a short period of time. To test for it, bring the engine to operating temperature. While the engine is running, hold the negative probe of a DVOM to battery negative terminal. Remove the radiator cap and hold the positive probe in the coolant. Voltage reading must be less than .3VDC If voltage reading is higher, locate and repair poor engine ground and or poor body ground. Ionized coolant can also cause electrolysis. Use of proper coolant and regular service intervals will prevent ionization of the coolant.