Radiator Coolant

Engines produce heat (and lots of it). During regular operation, your engine expels heat via the engine block and its related systems. However, over half of the energy produced by the engine remains inside the engine block.

That's where engine coolant comes into play. Coolant helps absorb the excess heat produced by the engine. Without good engine coolant, you run the risk of your engine overheating and seizing up during the hot Australian summer. Overheated engines aren't something to scoff at: the probability of permanent engine damage something you'd certainly rather avoid.

How Often Should I Change My Coolant?

There's no set answer for often you should flush (change) your engine coolant. As a general rule, check with your carmaker to see what they recommend. Broadly speaking, you'll find that most car manufactures recommend an engine coolant change every 50,000 to 80,000 kilometers. If you use your engine for heavy towing or hauling, you may want to change your coolant more often.

How Do I Know If I Should Change My Coolant?

Never rely solely on numbers to determine when you need an engine coolant change. If your coolant is any of the following, you'll need a coolant change:

• Brown or brownish in colour
• Opaque or difficult to see through
• Thick, sludgy, or discoloured

Other signs that a coolant change is in order include:

• Engine service lights
• Engine temperature fluctuations and warnings
• Steam rising from the engine

WARNING: Never open your radiator/coolant system when the vehicle is HOT! Of course, if you see smoke rising from the engine, pull over immediately and do not risk driving further until a mechanic addresses the problem.

Lastly, if you live in a hot climate (like we do in Australia), consider changing your engine coolant a little more regularly as vehicles operating in hot climates may, in some cases, suffer from premature degradation of engine coolant. Check with your mechanic often regarding the health of your engine coolant.

Types of Coolant

There's more types of coolant than you can shake a stick at. There are three main types of coolant that automotive manufacturers use:

1. IAT: Inorganic Additive Technology (the legendary "green stuff").
2. OAT: Organic Acid Technology (purple, orange, red, yellow).
3. HOAT: Hybrid Organic Acid Technology (orange, yellow)

As a general rule, IAT needs to be changed regularly (every 40,000 kilometres or so). Car manufacturers haven't used IAT in new vehicles since the late 90s/early 2000s, so it's mostly for older vehicles. OAT gets a pleasant 5 year, 80,000 km service interval. HOAT is roughly the same as OAT, but check your owner's manual to be sure.

Tip: Don't rely on color alone to determine coolant type. Check your owner's manual, car marker’s website, or local mechanic before risking damage to your engine.

What is Concentrate Coolant vs Pre-mixed Coolant?

There's a running debate regarding concentrated vs premixed engine coolant. Broadly speaking, premixed, ready-to-use coolant is best for someone looking to top up their coolant quickly. With coolant concentrate, you'll need to carefully mix in the correct amount of water. If you're looking for convenience for most practical purposes, go with a premixed coolant.

Another benefit is that premixed coolant tends to cost less than an equivalent amount of concentrate. Valvoline, for example, offers premixed ready-to-use coolants (both G-05 and Dex-Cool). Other options include Castrol's Radicool Premix and Nulon's Green Premium.

That said, concentrated engine coolant is best suited for anyone looking to customize their coolant system. Concentrated coolant lets you mix in the exact amount of water you need for your particular need.

As a general rule, opt for premixed engine coolant. If you'd be better off with concentrate, you'd already know.

Every major coolant manufacturer (Valvoline, Castrol, Nulon, etc) produces a concentrated engine coolant. As always, check with Automotive Superstore if you're unsure about which product is best for you.

What's the Best Coolant to use?

The easy answer? The correct radiator coolant for your vehicle is the best coolant to use.