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How to Check Your Car’s Oil, Coolant and Other Fluids

Check your car’s fluids once a month and before long trips. Park on level ground with the engine off and cool, pull out the oil dipstick, wipe it, push it back in and read the level between the minimum and maximum marks. Then check the coolant, brake fluid and screen wash reservoirs against their MIN and MAX lines, and top up only with the types listed in your owner’s manual.

Updated
Time
15 minutes
Difficulty
Easy

By Published Oct 9, 2026

Quick answer

  1. 1 Park on level ground, turn the engine off and let it cool for at least 10 minutes.
  2. 2 Open the bonnet (hood) and find the dipstick (usually a yellow or orange handle).
  3. 3 Pull it out, wipe it, push it fully back in, pull it out and read the level.
  4. 4 Top up oil a little at a time through the filler cap if it’s near the minimum.
  5. 5 Check coolant and brake fluid against the MIN and MAX marks with the engine cold.
  6. 6 Fill the screen wash bottle.
  7. 7 Get a mechanic to check anything that drops quickly.
On this page
  1. Before you start
  2. Get ready safely
  3. Check and top up the engine oil
  4. Check the coolant (antifreeze)
  5. Check brake fluid, power steering and screen wash
  6. Troubleshooting
  7. Frequently asked questions

Before you start

  • Your car’s owner’s manual (for fluid types and locations)
  • A clean rag or paper towel
  • The correct engine oil, coolant and screen wash for your car
  • A funnel (recommended)
  • Disposable gloves (optional)

Method 1 Get ready safely

  1. Step 1: Park on level ground

    A slope gives a false reading. Apply the parking brake and turn the engine off.

  2. Step 2: Let the engine cool

    Wait at least 10 minutes so the oil drains back into the sump. Check coolant only when the engine is fully cold. Some manufacturers recommend checking oil with the engine warm, so follow your manual.

  3. Step 3: Open the bonnet

    Pull the bonnet release lever inside the car (usually near the driver’s footwell), find the safety catch at the front of the bonnet, lift it and secure it with the prop rod if there is one.

  4. Step 4: Identify the parts

    Your manual shows a diagram of the engine bay. Caps for things you can check yourself are usually brightly coloured (often yellow or blue) and marked with symbols.

Method 2 Check and top up the engine oil

  1. Step 1: Find the dipstick

    Look for a loop handle, usually yellow or orange, sticking out of the engine. Some newer cars have no dipstick: check the oil level in the dashboard menu instead.

  2. Step 2: Wipe and re-insert

    Pull the dipstick out, wipe it clean, push it all the way back in, then pull it out again.

  3. Step 3: Read the level

    The oil should sit between the two marks (dots, notches, lines or a hatched area) at the tip. The gap between minimum and maximum is often about 1 litre (1 quart).

  4. Step 4: Check the colour

    Honey-brown to dark brown or black is normal. A milky or frothy look can mean coolant is getting into the oil; have it checked. A burnt smell or grit also needs attention.

  5. Step 5: Top up if needed

    Unscrew the oil filler cap (marked with an oil-can symbol) on top of the engine. Using a funnel, add the oil grade from your manual (for example 5W-30) in small amounts, about 200 ml at a time, waiting a minute and re-checking until the level is near the maximum.

  6. Step 6: Don’t overfill

    Too much oil can damage the engine and catalytic converter. If you overfill a lot, have the extra drained.

Method 3 Check the coolant (antifreeze)

Never open the coolant cap on a hot engine. The system is under pressure, and boiling coolant can spray out and cause serious burns.

  1. Step 1: Find the expansion tank

    It’s a translucent plastic bottle, often with a pink, blue, green or orange liquid, and a cap with a warning symbol.

  2. Step 2: Read the level cold

    The level should be between MIN and MAX on the side of the tank.

  3. Step 3: Top up correctly

    Use the coolant type in your manual, pre-mixed or diluted as instructed. Never mix different types without checking they’re compatible.

Method 4 Check brake fluid, power steering and screen wash

  1. Step 1: Brake fluid

    Find the small reservoir, usually near the back of the engine bay on the driver’s side. The fluid should be between MIN and MAX. A low level can mean worn brake pads or a leak, so have the brakes checked rather than just topping up.

  2. Step 2: Power steering fluid

    Many modern cars have electric power steering with no fluid. If yours has a reservoir (often marked with a steering wheel symbol), check it against the marks.

  3. Step 3: Screen wash

    Open the cap marked with a windscreen and spray symbol and fill it with screen wash. In freezing weather, use a winter mix rated for low temperatures. Plain water can freeze and doesn’t clean well.

How often to check
Fluid How often Warning sign
Engine oil Monthly and before long trips Oil warning light, burning smell, blue smoke
Coolant Monthly Temperature gauge high, sweet smell, steam
Brake fluid Monthly Soft or spongy pedal, brake warning light
Screen wash Every couple of weeks Low washer warning
Power steering (if fitted) Monthly Heavy steering, whining when turning

Troubleshooting

The oil level drops between services

Some oil use is normal, but if you add more than about a litre every 1,500 km (1,000 miles), look for leaks under the car and ask a mechanic to check.

The dipstick reading is hard to see

Hold the dipstick against a white paper towel, or check in better light. Clean oil can be almost transparent.

The coolant keeps going down

Look for drips under the car or white smoke from the exhaust, and get the cooling system pressure-tested. Don’t just keep topping up.

Frequently asked questions

Should I check oil with the engine hot or cold?

Most manuals say warm but turned off for 5–10 minutes, or cold before your first drive. Follow your manual. Always check coolant cold.

Can I use any engine oil?

No. Use the viscosity grade (such as 0W-20 or 5W-30) and specification listed in your manual. The wrong oil can harm the engine and affect your warranty.

How often should the oil be changed?

Follow your service schedule, typically every 10,000–30,000 km or once a year, depending on the car. Topping up isn’t a substitute for an oil change.

Summary

Once a month, park level, let the engine cool, and read the dipstick after wiping it once. Top up with the correct oil in small amounts, check coolant and brake fluid against their marks only when cold, and fill the screen wash. Treat red warning lights and fast-dropping levels as a reason to see a mechanic.

Written by

James Chambo

Founder

James is the Founder and Senior Editor of OnlineHow with more than 20 years of experience in internet publishing.