Radiator Flush and Cleaning

A Cooling System Flush

The best way to avoid a radiator repair is a cooling system flush. Flushing out a cooling system will remove old and worn-out antifreeze and helps to remove dirt and sludge. A cooling system flush and changing your antifreeze is the simplest way to help keep your radiator clean and prevent corrosion. Every vehicle needs regular oil changes, and your engine also needs a regular cooling system flush, Coolant levels should be regularly monitored and changed or top off as needed. The coolant in your radiator helps keep your engine from freezing at low temperatures, and not overheating at high temperatures. Antifreeze also comes packed full of additives which help to maintain your cooling system.

Antifreeze Additives

The antifreeze additives your vehicle uses will depend on what types of metal your cooling system has, what country the vehicle was manufactured in, the vehicles age, and which antifreeze you are using. The additives needed in your antifreeze will depend on  what type of radiator you have, an aluminum radiator, or a copper and brass radiator.

Your cooling system may use an ethylene glycol-based antifreeze, which as it ages, can become oxidized and turn into formic, oxalic, acetic, glycolic or glyoxalic acid. Additives are used to help protect your vehicle against these corrosive acids from forming in your cooling system. Your antifreeze may use nitrites, silicates, or borates to help prevent a corrosive environment on metal. Ethylene glycol antifreeze has a sweet taste and is very toxic. It will kill animals and yourself. Always handle with care and dispose of properly.

Other vehicles may use a propylene glycol base. This base is less toxic to yourself and pets but still needs to be handled properly. Propylene glycol oxidizes when exposed to air and heat and forms lactic acid which can be very corrosive. Additives, like phosphate, and bicarbonate can be used to control the corrosive nature of this antifreeze.

Your coolant may use an OAT antifreeze which stands for organic acid technology. OAT antifreeze claims to have over double the life expectancy and miles of other antifreeze.  OAT antifreeze has been very controversial in the past, and some had said that this antifreeze can attack gaskets and nylon and silicone rubber parts.

All of this can become very confusing to the consumer and your best bet is to change your antifreeze and flush your cooling system on a recommended schedule according to your owners manual. Also do not mix or change colors of your antifreeze and if you have to top off your cooling system, do so with the same type of antifreeze you already have in the system mixed with a  50/50 blend of antifreeze and distilled water.

Coolant maintenance

To prevent excess heat and the breakdown of your coolant make sure correct levels of coolant are  maintained. It is a good idea to check all fluid levels on your vehicle during each oil change, including your radiator coolant level. Checking your cooling system fluid level can be done by checking the reservoir tank. On the side of the reservoir tank is a fill hot line and a fill cold line.  If your vehicle is hot the coolant should be up to the hotline and if it is cold it should be lower, at the fill cold line. If your coolant levels are low, you should refill or “top off” the tank with a 50/50 mix of coolant and distilled water using the same type of antifreeze currently in your system. Never work on a hot vehicle and never open a hot cooling system. Cooling systems are under pressure and opening a pressurized cooling system can lead to extreme burns and eye damage.
When checking antifreeze levels, note the color of the coolant. The color of antifreeze should never change. If the color of your coolant has changed there is a good chance your antifreeze is old and needs to be replaced. A coolant color change may also indicate that you have corrosion or a transmission oil leak or an engine oil leak within the cooling system. In any case you will need to change the antifreeze and flush the cooling system to remove any contaminants. After any coolant change, make sure you check the complete cooling system to see if you need any repairs or a replacement radiator. Remember,  antifreeze discoloration could be caused by the expired coolant. It is important to completely flush out and replace old coolant based on the type of antifreeze you have and what your owner’s manual calls for, and never mix antifreeze types or colors.

Flushing your Cooling System

To properly flush and replace the coolant in your radiator, first make sure your engine is off and has completely cooled. Always check your top radiator hose before removing the radiator cap. It should be cool and easy to compress, indicating little to no pressure in your cooling system and. Completely drain your radiator into a drain pan, and be sure to properly dispose of the coolant, and keep all pets away, coolant should always be considered toxic,

Rinse the radiator and the complete cooling system with water until it runs clear. Rinsing is especially important if you had to add stop leak to your cooling system. You will then refill the cooling system with the appropriate 50/50 mix of water and antifreeze. This is a great time to check all hoses and belts replace any that show wear or have been on the vehicle for the recommended time frame. Hoses and bests are wear items and may look good but will need to be changed on a time schedule.

After refilling, it is important to ensure all air pockets or air bubbles are removed. Leave your radiator cap off and allow your car to run with the heater on for about 15 to 20 minutes. When you see the coolant circulating and the top hose is hot your thermostat is open. Double check your fluid levels and add any antifreeze needed to bring the fluid level up to the fill hotline. You can now replace the radiator cap tightly and you should be good to go.  It is also a good idea to check the coolant level after driving the vehicle after any system flush or part change. Always keep your eye on the temperature gauge and double-check everything after any work on your cooling system.

No matter what kind of antifreeze you have, for the antifreeze and additives to work properly, you will need to make sure that you:

  • Change your antifreeze on schedule.
  • Mix your antifreeze and distilled water using a 50/50 formula.
  • Do not mix your antifreeze with a non-compatible antifreeze.
  • Flush the cooling system to help remove any dirt and sludge.
  • Maintain the correct coolant levels of all fluids.

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