Whether it’s oil, coolant or gasoline, fluids are the lifeblood of your car.

While they vary in importance, all fluids are essential. After all, they’re the reason your vehicle even starts.

“When it comes to vehicle fluids, it’s better to be proactive than reactive,” said Travis Mock, supervisor for club-owned auto repair for AAA Arizona. “Simple and fairly inexpensive maintenance duty can result in hundreds or even thousands of dollars of damage if ignored.”

The average car contains eight types of fluids. Here’s a rundown of each.

  • Gasoline:
  • Besides running the vehicle, fuel acts like a cooler for the fuel pump inside the gas tank. As a result, don’t consistently run your tank low, so your fuel pump doesn’t overheat. Generally, a fuel tank leaks only if it has been punctured. And it’s a pricey fix: Though today’s fuel tanks are made of plastic to reduce vehicle weight, they still cost hundreds to replace.
  • Oil:
  • If you’re going to have a leak, chances are it will be from oil. You’ll know you have one when the pavement where you park your care develops a darkish stain. Oil is designed to minimize friction inside the engine and keep the engine cool. It’s important to catch and fix oil leaks quickly. If oil drips on any of the multitude of rubber components under the hood, it will emulsify them. Mock recalls seeing an oil drip that had melted a hole through a radiator hose after just a few months.
  • Power steering fluid:
  • This lubricant and detergent keeps the power steering system clean and should be changed every 30,000 to 50,000 miles. If you wait too long to change it, the fluid becomes acidic and will break down seals. Power steering fluid tends to be reddish or yellowish in color with a graphite-like odor. If you’re low on this fluid, it will be obvious from the groaning noises that occur when you steer. Most vehicles take 1 to 2 quarts.
  • Transmission fluid:
  • This fluid looks similar to power steering fluid and also acts as a lubricant and detergent. A whopping 14 to 16 quarts usually are required, and the fluid should be changed every 30,000 miles. Leaks often occur by the transmission cooler, which tends to be near the radiator, in the lines that connect to it or the transmission itself. A telltale sign that you might be running low is when the transmission will not shift through its gears properly.
  • Brake fluid:
  • This fluid resembles yellow-tinged water and washes off fairly easily. Because moisture can kill any brake system, brake fluid is designed to pull water from the system. Over time, the moisture content will overpower the 8 to 13 ounces of fluid and reduce performance, so change this fluid usually every 30,000 miles. Mock cautioned that the bitter-smelling fluid does not evaporate, so it never should be topped off. Topping off the fluid will eliminate the secondary indicator saying that the brakes are due. Mock said if the brake fluid is low, it’s either leaking or the brake pads are worn out.
  • Coolant:
  • This is a common leak and can be red, yellow, blue or green with an oily feel. This also is the fluid that smells fishy and tastes sweet, which is why many pets die from drinking it. Its purpose is to lubricate and pull heat away from the engine or parts. The 2 or 3 gallons of coolant should be changed every 60,000 miles or before the fluid gets so old that it loses its abilities.
  • Differential:
  • Rear-wheel and all-wheel vehicles require differential fluid, which lubricates the drive axles. For most of these cars, it should be changed every 30,000 miles. With its amber color, differential fluid resembles engine oil. You might see spots on the pavement that look like an oil leak. This type of leak tends to come from a seal. AAA Auto experts said if the fluid all leaks out (about 4 pints), you’ve got moving metal components without any lubrication, resulting in a very pricey fix.
  • Windshield wiper fluid:
  • This fluid isn’t that important — that is, until you have a dirty windshield and can’t see. The average plastic tank holds 1 gallon of the blue liquid, which contains distilled water and a glycol base to prevent it from freezing.

AAA auto experts advise drivers to consult their owner’s manuals for recommendations on when to change the fluids in their vehicles.

Valerie Vinyard is a public affairs specialist at AAA Arizona. Contact her at vvinyard@arizona.aaa.com or at 258-0518.