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Open the bonnet, spot the symbol

The caps under your bonnet are marked with small standard icons, not words. Here's what each one means and where to expect it.

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This page is just the "what am I looking at" reference. For the actual step-by-step on checking levels and topping each one up safely, that's over on Maintenance.

These are the six fluids and caps you'll find on almost every petrol or diesel car — some vehicles (EVs, certain hybrids) won't have all of these.

Want the how-to, not just the symbol?Go to Maintenance →
Oil can, dripping

Engine oil

Usually a bright yellow cap, often with an oil-can-shaped icon moulded straight into the plastic.

Top of the engine, fairly central and easy to spot.
Thermometer in waves, or "coolant"

Coolant

A translucent plastic reservoir tank with min/max lines on the side — you can usually see the fluid level without opening it.

Often near the radiator, sometimes labelled instead of symbol-only.
Never open when the engine's hot — it's pressurised.
Circle with an exclamation mark

Brake fluid

A small reservoir, usually near the back of the engine bay on the driver's side, often marked "DOT 4" or similar.

Level drops very slightly as brake pads wear — that's normal.
A sudden drop is not normal — get it checked, don't just top up and ignore it.
Windscreen with spray lines

Washer fluid

Usually a blue cap with a windscreen-and-jet symbol — the cheapest and easiest one to top up on any car.

Often towards the front or side of the engine bay, blue cap is the giveaway.
Steering wheel icon

Power steering fluid

Only relevant on older or hydraulic-assist cars — many modern cars use electric power steering with no fluid at all.

If your car has it, usually a small reservoir near the steering rack or belt area.
Battery symbol

Battery (12V)

Sealed on most modern cars, so there's no fluid to check — just terminals to keep clean and tight.

Usually a black box with red/black terminal caps, corner of the engine bay.
Symbols vary a littleManufacturers don't all use identical icons, but they're close enough across brands that once you know the general shape (a can for oil, a windscreen for washer fluid), you'll recognise it on almost any car. If in doubt, your handbook has an "under the bonnet" diagram that names everything exactly.

General reference based on widely-used automotive convention for under-bonnet fluid caps and reservoirs. Exact symbol design, cap colour and reservoir location vary by manufacturer and model — always confirm against your own vehicle handbook before working under the bonnet.