Looking After Your Radiator It is imperative that the correct coolant is used and that it is well maintained to ensure long life from your radiator. Coolants must not be mixed and must be replaced when stipulated by the manufacturer - it may look the same after this date, but may no longer be doing its job. Aluminium is normally seen as corrosion resistant because an oxide layer forms on the exposed surfaces that acts as a barrier to further corrosion. However, in conditions where this barrier is broken, corrosion can be very rapid as aluminium is actually a very reactive metal. This is why care of the coolant becomes even more important when using an Aluminium radiator. Copper/brass cores are quite tolerant to water quality and although there are some chemicals that can cause problems, and corrosion inhibitors must be used, normal tap water is reasonably well tolerated. The same does not apply to aluminium cores. A few important points to note regarding coolants: Use the correct coolant specified for the vehicle. Coolants are selected to suit the vehicle. The requirements for aluminium and copper brass radiators are different and a common coolant may not suit. The radiator is not the only part of the coolant system and some coolants may have been selected to protect other parts of the cooling system. Use the correct concentration of coolant. Coolants for aluminium radiators are mainly composed of ethylene glycol but also contain chemicals to protect the cooling system. High-ethylene glycol content will actually reduce the heat rejection performance of the cooling system*. This results in the engine running hotter than normal when the thermostat is fully open. Always use good quality water to blend with the coolant. Distilled water, demineralised water or rain water are the preferred options. Many town water supplies contain high concentrations of chemicals, such as salts, that are very damaging to an aluminium radiator. Do not mix coolants. Many coolants use different chemical systems and combining them may neutralise the effect of the chemical protection. Replace the coolant at the specified intervals. During service the ethylene glycol eventually deteriorates and becomes acidic. This acid will attack the internal oxide coating on the aluminium and lead to corrosion. Flush the coolant system with clean water after the coolant is drained. It is important to remove any scale or deposits from the system and remove old coolant and chemicals that may adversely affect the new coolant. The heater core is part of the cooling system and must also be flushed of coolant. Check that the system is properly filled and that any air is removed. Air in the coolant will increase the rate of corrosion and air pockets can lead to uneven cooling of the engine. Some vehicles have trapped air pockets and it may be necessary to bleed air from vent positions to allow the air to escape. The vehicle should be run for a while before the cap is replaced to allow the air to escape. If the coolant is topped up it should be with a properly mixed coolant solution so that the concentration of the system is not changed. Ensure that the coolant type is the same as is already used in the vehicle to ensure it is compatible. *Low-ethylene glycol content will not carry the required concentration of additives and can also result in an incorrect Ph level. This leads to damage of the radiator due to corrosion. NOTE: Ethylene glycol is toxic. Please follow specific manufacturer instructions for handling and disposal. It is also important to clean up spills. Radiator Service DENSO advise the use of authorised radiator repairers or your vehicle dealer. Generally, cooling systems should be serviced yearly. Your radiator specialist will flush and replace your coolant, clean off road debris and check for possible problems such as corrosion, blockages, leaks, hose wear and tear, etc. Preventative maintenance assists in preventing breakdown due to over-heating. Genuine parts are recommended for optimal efficiency as these parts are designed specifically for the vehicle model. A change of components may affect performance of the cooling system. DENSO copper/brass NWR and NSR radiators may be replaced with equivalent DENSO Aluminium NSR radiators in some instances. In these cases the direct equivalents have been designed to suit the application. Radiator Care Ensure radiator coolant level is correct. In newer cars this is as easy as looking through the plastic reservoir wall to check fill lines are covered. Coolant can be added via the reservoir (when cold) if required (refer to section on coolants). For vehicles without a reservoir, remove the radiator cap and check coolant level while the engine is cold. Also check if coolant looks rusty, or has things floating in it - if it does, the system needs flushing and new coolant. If it has a sludgy oily surface get your mechanic to check for the reason. While checking the radiator, ensure that the hoses are not leaking, cracked, bulging or squishy. If they are, they will need to be replaced. What to do if your car overheats If your radiator overheats, pull over and raise bonnet to assist cooling. Do not remove radiator cap or add cold liquid. Allow time for the radiator to cool down, liquid should only be added to the radiator when it is cool. Apart from the danger of being burnt by the radiator, removing the cap when hot will cause hot liquid and steam to surge upwards as the pressure in the system is released. Adding cold liquid to a hot radiator can also crack the engine block. If you must add liquid while it is still a little warm have the engine running to mix the cooler liquid as it is added and add slowly. Causes of Premature Radiator Failures Corrosion - Internal & External Erosion - Internal & External Stray Current - Electrolysis Mechanical Damage Chemical corrosion is often due to incorrect coolant use. Corrosive atmospheres, road grime and stray current in the cooling system are also potential problems. Qualified Auto Electricians and Radiator Repair Specialists use a voltmeter and a specific procedure to test for stray current. Mechanical failure includes tanks splitting and separation of fin to tube bonding. It is often caused by excess pressure in the system, possibly from a blown head gasket or even a radiator cap. A faulty swollen radiator cap or incorrect one can prevent pressure release with severe consequences. Alternatively, poor radiator cap sealing can lead to the loss of coolant, loss of system ability to draw coolant back from the overflow reservoir and to boiling of the coolant under severe operating conditions. This information is care of one on my radiator manufacturers - denso.au/Products/Automotive/Radiators/Technical-Information/Looking-After-Your-Radiator
Posted on: Thu, 19 Jun 2014 11:06:57 +0000
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