When was the last time you changed your vehicle’s anti-freeze? Engine coolant, often called anti-freeze, protects your vehicle’s cooling system against internal corrosion and your engine from overheating. However, with time and use, coolant becomes more acidic, losing its ability to prevent rust or safeguard your engine from “boiling over”.
Fortunately, changing your coolant is an easy DIY job that will extend the life of your cooling system and your engine. Most manufacturers recommend changing your car’s coolant every three to five years or 30,000 to 50,000 miles. If your engine coolant looks rusty it’s definitely in need of replacement. But there’s more to it than just draining and refilling the radiator.
Here’s a list of expert tips and tricks that will help you get the job done correctly and more importantly, safely.
When you're changing your car’s coolant, it’s vital that you start with the engine completely cold. In doing its job to cool down the engine, the coolant absorbs heat from the engine so that under normal operating conditions, your car’s engine coolant is about 200 degrees Fahrenheit and under extreme pressure. Opening the radiator cap of a warmed-up engine is extremely dangerous; you could get a face full of scalding steam.
Attempting to cool down engine coolant by introducing cold water to a hot engine can also cause thermal shock, potentially warping or cracking your engine block or cylinder head.
Filling your cooling system with water instead of coolant might seem like a cheap solution, but it’s risky. Water contains minerals and other impurities that cause scale to build up inside the cooling system, reducing its efficiency and eventually leading to overheating.
The water will also freeze in cold temperatures, which will crack your engine block. Coolant keeps this from happening, which is why it’s often referred to as anti-freeze. But using straight coolant can also do harm so don’t do it.
Always consult your owner’s manual for the manufacturer’s recommended coolant type before you hit the store. Many engines contain aluminum and other alloys sensitive to coolant type. Using the wrong kind could result in corrosion problems, overheating and other damage down the road.
Many coolants on the market today are premixed with a 50/50 blend of coolant and water that can be poured directly into your radiator. If you insist on doing the mixing yourself, typically in a 1:1 ratio, use distilled water, which contains fewer minerals and impurities than tap water.
Even after you empty the radiator, as much as a quarter of the old coolant will remain in the engine block. You'll need to unscrew the engine block drain plug to get the rest of that fluid out. The plug is usually found on the side of the block, roughly a third of the way from the bottom. If you can’t easily find the plug, check your vehicle’s service manual for its exact location.
Otherwise, when you refill the system, your fresh, new coolant will quickly become contaminated with the rust, scale and other impurities left behind in the old stuff.
When changing your coolant, install a new thermostat and radiator cap. These often overlooked but relatively inexpensive components keep your cooling system working like new.
The thermostat is a temperature-sensitive valve that regulates the flow of coolant between the engine and the radiator. With time and use, it can become stuck open or closed, causing the engine to run too hot or too cool.
Likewise, the radiator cap, which maintains pressure within the system, can deteriorate with age, leading to leaks and eventually overheating.
Tinker Experts recommend replacing the radiator cap at least every five years and the thermostat every ten. If you aren’t sure when yours were last changed, now's the time.
Air pockets can form in the cooling system during the process of draining and refilling, and it's important to expel such bubbles. Otherwise, they impair coolant flow, leading to hot spots and overheating.
Begin by removing the radiator cap and starting the engine. That gets any trapped air moving through the system. Then monitor coolant levels while the engine idles, topping it off as air bubbles escape. To be extra careful, also, gently squeeze the upper radiator hose to dislodge any air trapped inside, being mindful that the hose may be hot. Continue until you no longer see any bubbles and then replace the radiator cap.
After you’ve successfully changed your coolant, there’s one final step: proper disposal of the old coolant. Coolant contains toxic substances like ethylene glycol, so pouring it down the drain or onto the ground not only contaminates water supplies and soil but also puts pets and wildlife at risk because they are attracted to its sweet taste.
To dispose of old coolant properly, collect it in a sealed container and take it to a recycling center or hazardous waste disposal facility. Alternatively, some auto parts stores will take it off your hands – call ahead and find a location that will that care of yours.
Still have questions? Speak to one of our Tinker Experts today!
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