The 6 Fluids in Your Car (And Why Letting One Run Low Can Cost You Thousands)

Your car runs on more than fuel. There are six key fluids quietly keeping everything working, and letting any one of them run low or go off can turn into a very expensive day. Here's what each one does and how to keep an eye on it.

Engine oil. The most important one, and the one to check most often. Pull the dipstick when the engine's cold and the car's on level ground, wipe it, dip it again and read the level. Low oil, or oil that's gone thick and black, means it's overdue for a change.

Coolant (radiator fluid). This stops your engine overheating in summer and freezing in winter. Check the level in the overflow reservoir — never open a hot radiator cap, the pressure can scald you. Low coolant, or a car that runs hot, is a job to sort quickly: overheating warps cylinder heads, and that's four-figure territory.

Brake fluid. Safety-critical. Brake fluid absorbs moisture over time, which lowers its boiling point and makes the pedal feel spongy or fade under hard use. It should be clear to light gold; dark brown means it's due for a flush. Low brake fluid can also be a sign of worn pads, so it's always worth a look.

Transmission fluid. This keeps your gearbox shifting smoothly, and neglected transmission fluid is behind a lot of expensive auto rebuilds. Many modern autos are "sealed" with no dipstick, so this is one to have checked properly during a service rather than at home.

Power steering fluid. If your steering has gone heavy, or you hear a whine when you turn the wheel, check this. Running the pump on low fluid wears it out fast.

Washer fluid. The cheapest and least dramatic — but a clear windscreen is a genuine safety issue, especially with Western Sydney's bug season and dusty westerly winds. Top it up with proper washer fluid rather than plain water, so it doesn't go green and clog the jets.

The big-money fluids are coolant, brake and transmission — get those wrong and you're up for serious repairs. Oil is the one to check most often. Washer is the easiest. A proper service goes over all six so you don't have to remember.

Need a hand? Call Mehdi on 0424 334 080 — mobile mechanic across Western Sydney.