Automotive Fluids You Thought You’d Never Change

Several automotive fluids are critical to your vehicle’s longevity and reliability. Some you deal with on a weekly basis, others a few times a year, and still others you might not even know about. For example, the fuel gauge tells you when it’s time to add gasoline, diesel, or ethanol. Since your tire pressure varies depending on the season, and all tires lose air, you should check and adjust your tire pressure at least monthly.

Automakers typically recommend fresh engine oil every 5,000, 8,000, or 15,000 km, depending on the car’s year, make, model, and oil type. Synthetic oil tends to last longer than conventional oil, but all engine oil additives wear out, evaporate, and burn off. The remaining oil also heats up and oxidizes, leaving ash and other deposits.

Normal driving vs. severe driving

No one wants to admit they’re a severe driver, but it’s not all about who’s behind the wheel. It’s also about ideal driving and less-than-ideal driving conditions. Most cars should follow a severe maintenance schedule and have shorter service intervals, because short trips, stop-and-go traffic, and extreme weather shorten the life of a vehicle and its automotive fluids.

The “forgotten” automotive fluids

Thanks to advances in automotive technology, manufacturing methods, and fluid technology, cars last longer than ever. The average Canadian car is nearly 10 years old. If your vehicle is over three years old, consider these automotive fluids to keep the odometer turning.

The brake system is the most critical component of your car. Brake fluid is hygroscopic, absorbing and retaining water and preventing dangerous brake failure, but it eventually becomes saturated. The water also accelerates corrosion within the braking system—and Canadian cars already face corrosion from road salt and traction sand. It is usually recommended that you replace your brake fluid every three years or 50,000 km, or when the brakes are replaced or serviced.

Engine coolant (also called antifreeze) is a blend of water, alcohol, and additives that moderates your engine temperature, lubricates the water pump, maintains seals, and prevents corrosion. As additives evaporate, the engine coolant can become acidic, accelerating corrosion from within the engine, heater core, and radiator. Acidic coolant can even cause electrical problems. Many long-life coolant blends are replaced around 150,000 km, then every 75,000 km.

In the last decade, automatic transmissions and automatic transmission fluid (ATF) have advanced significantly, and some automakers don’t specify an automatic transmission fluid change interval. In fact, some aren’t even equipped with dipsticks, as they’re ostensibly “filled for the life of the vehicle.” Given the 10‑year or 240,000‑km lifespan of a Canadian car under “normal driving” conditions, an automatic transmission fluid change is a good idea.

Power steering fluid (PSF) is the last forgotten automotive fluid on our list. Your vehicle may not even be equipped with a hydraulic power steering system, as many vehicles now have electric power steering. A fluid change interval may not be specified. If the fluid looks or smells burnt, flush it out with new power steering fluid, usually after three years or 50,000 km.

When it comes to automotive fluid change intervals, consult the owner’s manual for your car’s specific year, make, and model, adjusting for driving conditions. Remember, maintenance is always more convenient and less expensive than repair or replacement.

Check out all the category products available at or trust one of our 600 NAPA AUTOPRO shops for routine maintenance and repairs. For more information on automotive fluid change intervals, chat with an expert at your local NAPA Auto Parts store.

By Benjamin Jerew

1 Reply to “Automotive Fluids You Thought You’d Never Change”

  1. Desmond Hangnail says:

    As a longtime car guy who used to do all my own maintenance this advice is very good and actually correct. Most is not and most is also vague. Thank you. Also add a water remover to your gas tank a couple of times a year.

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