Cooling System Flushing Procedure. Because coolant/inhibitors from different manufactures have different chemical compounds, which may adversely react if mixed, it is important that you DO NOT create a chemical ****tail within your cooling system by mixing different brands of coolant/inhibitor. Even though the coolant has been drained from the system, the inhibitors remain affixed to the cooling system components and must be chemically removed, using a quality alkaline flush. Procedure: 1: Ensure the cooling system is sound and free from leaks and check all components for wear and condition. If need, replace worn components. 2: Choose a quality alkaline cooling system flush (500mL. Per 12 Litres). Observe the instructions on the container. 3: Replace the radiator cap and run the engine at operating temperature for 15 minutes in 4 cylinder vehicles and 30 minutes in 6 or 8 cylinder vehicles. (Ensure the vehicle heater is turned on). 4: Drain and rinse the cooling system including the overflow bottle and heater core. At this point a power flushing machine may be used if this equipment is available. And/or: 4a). Rinse the system with clean water until you are convinced that the only fluid remaining in the system is clean water- RINSE- RINSE- RINSE (this may need to be refilled and drained a number of times). 5: Refill the cooling system using clean water (demineralised or distilled water), to perform a stray current check. 6: Do not add coolant at this time until a complete stray current check has been performed (refer to stray current procedure). The presence of stray current will deteriorate the cooling fluid quality immediately. Always ensure you select a coolant/inhibitor that meets the vehicle manufacturers recommendation or one that meets AS 2108-97 Type A or Type B whichever is recommended as being in support of the vehicles manufacturers recommended coolant performance standard. 7: Ensure the correct rates of coolant/inhibitor is used, as overdosing or underdosing will have a direct affect on the performance of the cooling system and the life of the components including the radiator. 8: Only after the vehicle has been cleared of the possibility of stray current (electrolysis). Rebuild the cooling fluids by first adding the selected product then topping up with clean water (demineralised or distilled water). NOTE: NEVER MIX TWO BRANDS OF COOLANT! 9: Mix a portion of the coolant for the owner to use for topping up coolant level. Dispose of Waste Fluid Correctly. NOTE ! Radiator manufacturers warranty does not cover internal or external corrosion.[COLOR="Silver"] ---------- Post added 17-03-11 at 19:29 ---------- Stray Current Testing Procedure. Diagnosing Electrolysis/Stray Current Corrosion Testing procedure. (Please Note It is recommended that a qualified Auto electrician or Radiator Repair Specialist carry out this procedure. Tools/Equipment Required. Voltmeter (multimeter) with a scale able to read in millivolts (Analogue voltmeter is preferred). Or A radiator industry designed stray current detector preset to 50mV. (0.05 volts) Target range below 50mV. However any voltage reading in the cooling system should be corrected, as further deterioration will cause major damage. Procedure. 1: Connect the voltmeter or current detector negative terminal to the battery ground and the positive terminal directly into the coolant (ensure not to touch the metal core or filler neck). 2: With the ignition on and again with the engine running, check EVERY component. Whilst you are monitoring the presence of stray voltage in the cooling system, have a fellow worker operate the brake lights, parking, head and high beam lights and indeed all electrical components (whether factory or aftermarket) and check for any increase in voltage readings in your voltmeter. Fail: If you get a reading above 50mV (0.05 volts) or a red fail light on the current detector. Do Not Proceed: The source of the current leakage should be found, as this can destroy a radiator in a short period of time (hours or days, depending on the level of voltage) and severely damage other engine components. It is highly recommended that all repairs or work carried out on a vehicles electrical system or component is carried out by a qualified auto electrician. Note: The cooling system cannot be successfully passed as being free from stray current voltage if the system contains coolant, it has been found that coolant may provide inaccurate readings. Pass: Only when the analogue voltmeter reads below 50mV (0.05 volts) or a green pass light is obtained should you proceed to fit a new radiator or recharge a cooling system with coolant. In both cases the flushing procedure should be followed prior to the vehicle being released. Note: Some coolants have been known to retain an electrical charge after the fault has been detected and repaired. All testing for stray current should be carried out using clean water (demineralised or distilled) after the flushing procedure has been carried out. It would be very wise to test the vehicle again in one or two days to ensure stray current related problems are corrected and coolant has settled down. Some original photos have not been recovered yet.