What’s the Purpose of Coolant?

Coolant, or antifreeze, does exactly what its name suggests. It keeps the engine from overheating and freezing. Typically, it’s a 50/50 mix of water and coolant. Sure, water can work solo, but in cold weather, it freezes, and in the heat, it evaporates—both scenarios spell disaster for an engine.

The color comes from dyes that help identify the type of coolant. Now, let’s break down the differences between green and orange antifreeze.

Green Antifreeze

Green antifreeze is the go-to for older vehicles, especially those made before 2000. These engines often have a lot of steel and copper parts, which need protection from rust and corrosion. That’s where Inorganic Additive Technology (IAT) comes in, mixing phosphates and silicones with either propylene glycol or ethylene glycol.

Phosphates help soften water and clear out dirt, while silicones act as a sealant, keeping moisture and chemicals at bay. The glycol? That’s the magic potion that prevents overheating.

Orange Antifreeze

On the flip side, orange antifreeze is tailored for modern cars that sport more aluminum and nylon components. It uses Organic Acid Technology (OAT) to fend off corrosion without messing with non-metal parts. This shift started in the 90s, leading to the introduction of DexCool, a coolant that keeps rust at bay.

While orange coolant is great, it can cause trouble if it runs low. Air can sneak into the system, leading to blockages and potential damage. Luckily, it can last up to five years if topped off regularly.

Mixing Different Engine Coolant Types: A No-Go

Mixing green and orange antifreeze? Not a smart move. They don’t play nice together and can turn into a gel-like substance. Your engine needs fluid, not goo, to keep everything running smoothly. If the water pump can’t do its job, it could lead to costly repairs—think $750 or more.

If switching types, it’s crucial to flush the system first, which can set back about $100.

Maintaining Engine Coolant

Keeping an eye on coolant levels is key. Green antifreeze typically lasts around three years or 36,000 miles, while orange can go for five years or 150,000 kilometers. A good rule of thumb? Check it during oil changes.

If it’s rust-colored, that’s a sign the rust inhibitor has worn out—time for a flush. Cloudy? That could mean oil is leaking in, which is a double whammy for engine health.

Feeling it between fingers can help too. If it’s gritty, it’s dirty, and a system flush is in order.