What is Antifreeze and Why you should Replace your Antifreeze at Manufacturer’s Specified Intervals

Lee Furlonger

Antifreeze is a liquid added to water to create engine coolant. Antifreeze helps lower the freezing point of the water and also increase the boil point. It contains anti-corrosive properties to protect the metallic surfaces of the engine’s various parts as well.

Over time antifreeze will lose these properties and needs to be replaced. Not replacing the antifreeze at the recommended intervals will result in the engine running at a hotter temperature with a risk of overheating. The engine is at risk of freezing in lower temperature possibly causing damage to engine and cylinder head core plugs, water pump and radiator. When the anti-corrosive properties are lost items the coolant system will start to corrode from the inside out, putting core plugs, water pump, radiator, block and cylinder at risk.

Antifreeze comes in two forms ready mixed and concentrate. Ready mixed is as it sounds pre mixed with water ready to pour into the coolant tank of the vehicle, ideal for top up. Concentrate needs to be diluted with water.

There are also various colours of antifreeze from lots of different vehicle manufacturers and aftermarket brands.

IAT Green – up to 2 years protection (pre 1990 vehicles)

OAT Blue – up to 2 years protection

OAT Red / Pink – up to 5 years protection

OAT Purple – up to 5 years protection

HOAT Yellow / Orange – up to 5 years protection

IAT – Inorganic Acid Technology is the traditional green stuff that is pretty much only used on older cars from the late 90`s.

OAT – Organic Acid Technology is used today because it offers silicate-free protection of all metals and for a longer period of time.

HOAT – Hybrid Organic Acid Technology is today, a mix of IAT and OAT and contains 10 percent recycled coolant

Generally you should never mix different colours of antifreeze, however some of the modern brands can be mixed together – always check your owners manual and the instruction of the antifreeze you have purchased for recommended guidelines.

Coolant levels should be checked regular and every 3 to 6 months should be check with a hydrometer to make sure the water/antifreeze mixture is correct and sufficient for the temperature the vehicle is operating in.

Never open the coolant head tank when the vehicle is hot! Always wait until the engine has cooled down before attempting to top up the coolant with antifreeze.

Checking or replacing antifreeze is a job every vehicle own can do and is a basic maintenance job free problem free driving. Your local motor factor will have various types of antifreeze available to purchase.

Author Bio:

Hooked on driving since the age of 7, Lee quickly picked up the basics of and settled in his current occupations which are mechanic and machinist. He loves anything mechanical and has a passion for keeping classic vehicles alive and on the road. I`ve been rebuilding engines and fixing cars since I was 17. Have a growing collection of 6 different vehicle all 80`s and 90`s models, mostly Fords. Also have a love for classic Land Rovers and off roading.

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