How to check car fluids! – Basic Car Skills

If you own and drive a car there are some things you should know. This includes how to check car fluids and repair basic things on your car. It doesn’t matter if you are 18 years old or 60 years old, male or female. These are the basics you should know for your own safety and for the wellbeing of your car. Some guides like this you find include skills like changing your own oil and filters. That’s too much. I would like to see people respecting and knowing when their cars scheduled maintenance is. I am always shocked when I hear about people not even knowing their car needs a regular oil change. This happens more often than you imagine.

This first part of the “Basic Car Skills” series covers checking all the important fluids in your vehicle.

It’s a long article, here are some shortcuts:

“Checking the engine oil level”
“How to check the brake fluid level”
“Checking the coolant level”
“How to check the windshield wiper fluid”
“Checking the transmission and differential oil”
“High fuel consumption causes”

How to check the engine oil level

Most of the new cars and all of the older cars will have an oil dipstick which serves you as an indicator of the oil level. Certain Audi’s and BMW’s don’t have the oil dipstick anymore (which is incredibly stupid) so you will have to rely on your dashboard reading of oil level. Here are a few simple steps to check your oil, and a great video explaining it with more detail.

Step by step guide for checking engine oil levels

  • Grab a lint-free clean cloth. An old t-shirt will do just fine.
  • Make sure your car was standing still for some time so all of the engine oil drains into the oil pan. This is the only way to check real oil levels. The best time to do it is in the morning.
  • Open up the hood of your car (the lever should be somewhere around your driver’s seat, google it or check the users manual if you have trouble). Locate the oil dipstick, it should look something like this:
  • Pull out the oil dipstick and wipe it off clean with the lint-free cloth you grabbed earlier. Take a look at the dipstick. Then check where the minimum and maximum levels are marked on the dipstick. Some dipstick will have “min” and “max” written on them. Others will just have 2 randomly shaped marks. The bottom mark is the minimum and the top mark is the maximum.
  • Dip the stick back in all the way down. Pull it back out again a few seconds later.
  • Check where the oil mark or stain ends. If the oil stain doesn’t reach the minimum mark, your car is running low on oil. If the oil stain exceeds the maximum mark you have too much oil in your engine, which is also bad.

    You want to see the oil level somewhere between the minimum and maximum level.
  • I like to repeat the whole process again just to make sure. Once you get the hang of it, it only takes a minute.
  • Based on your reading decide if you need to have some oil poured in your engine or even drained out of your engine. If you have some spare oil at home pour it in slowly and check your oil so you don’t pour in too much. Make sure it is the same oil that is currently in your engine, check the specs (5W-40 synthetic for example). If you don’t feel comfortable and you don’t know where and which oil belongs in your car, just visit a local mechanic.

    Also, have excess oil drained out by a mechanic. Excess oil causes unwanted pressure in the engine which can cause damage. If your oil levels are somewhere between min. and max. you are all set and ready to go. See this video for more information.

How to check the brake fluid

Next on the list and the most important one is the brake fluid. I think an explanation isn’t needed why brake fluid is so important to check on. The breaks on your car are hydraulic meaning the brake fluid connects your breaks and your brake pedal. When the brake pedal is pressed in and immediate pressure is applied through a plunger on the brake fluid which makes the brake pads to clamp and grip your brake discs. Your car starts stopping instantly.

If you feel like there is a delay between you stepping on the brake pedal and the car actually stopping, you need to check your brake fluid levels immediately. Brake fluid can get mixed with water which causes the brake lines to crack and leak. Other things as age and poor materials can also cause your brake lines to start leaking. If you are constantly losing brake fluid visit a mechanic as soon as possible. Little cracks and leaks of brake lines can turn into complete break failures which as you can imagine is extremely dangerous.

Step by step guide on checking the brake fluid

  • Open up your hood and look around the engine bay. There should be a small transparent reservoir with some sort of a sign that indicates brakes. Look at the picture below to get the idea.
  • Once you find your brake fluid reservoir identify the minimum and maximum levels that should be indicated somewhere on the side of the reservoir.
  • Once you find the min. and max. levels see where your brake fluid level is. Determine the level and act accordingly. It must be somewhere between the minimum and maximum mark, like all other fluids in your car.
  • Your brake fluid should be transparent and “colorful” not dark and dirty.
  • If you need to refill your braking fluid make sure to get a compatible one. Most places that sell brake fluid should know which one you need. If your brake fluid is dirty and dark you must have it replaced completely by a mechanic.

How to check coolant levels

Right of the bat: NEVER CHECK COOLANT LEVELS WHEN THE ENGINE IS HOT OR RUNNING. Doing that might result in coolant blasting out of the reservoir due to the pressure it is under. Coolant gets very hot and can cause serious burns. Coolants or antifreeze’s job is to cool down the engine and prevent it from overheating. Coolant drives the heat away from the engines and dissipates in the radiator. Having the right amount of coolant is crucial for this process to work and your engine to cool down.

Step by step guide for checking coolant levels

  • Your coolant reservoir (expansion tank), is placed somewhere under the hood of your car. Open the hood and take a look around the engine bay.
  • Locate the coolant reservoir. It is usually completely made out of transparent plastic or it has a black plastic top. Look for a reservoir that has a different cap with some warning signs because of the pressure and heat the coolant is under. The reservoir cap is sometimes made out of metal. Nowadays it is mainly made out of plastic but still looks a bit different than all other reservoir caps. That is because it is made to release excess pressure.
  • Determining the level of coolant varies from car to car. Most cars will have expansion tanks like the one on the picture above. There should be an indication of the minimum and maximum level of coolant. If you don’t have enough coolant make sure to buy and fill up the coolant with a compatible one. Again, if you aren’t comfortable doing this on your own, visit a local shop and they will gladly do it for you. Just learn how to check the levels on your own.

    Some cars do not have such expansion tanks in which case there should be a cap on top of the radiator. Open the cap and check if the coolant is nicely topped up, that’s it.
  • If you have compatible coolant at home, topping up is really simple. Make sure to pour it in slowly and wait for air bubbles to “burp” out. Don’t overfill the expansion tank!
  • If you are losing coolant on a regular basis, have your cooling system checked for leaks or any other damages. Sometimes it can be just a bad seal on one of the hoses, or it might be a damaged radiator.

How to check the windshield wiper fluid

There isn’t a visible reservoir or container for the windshield wiper fluid. In most cars what you will see is just the cap that leads towards the reservoir which is hidden deeper in the engine bay. Windshield wiper fluid is essential for safe driving which makes it as important fluid as any other. When you are running low on windshield wiper fluid, your car will most likely warn you about it with a warning light on the dashboard.

Refilling windshield wiper fluid is simple. Buy the windshield wiper fluid at the local petrol station or auto parts store, open the lid under the hood and pour it in until it full. Be careful when buying the windshield wiper fluid in the winter. Make sure it is made for cold temperatures if you live in a place with cold winter. Windshield wiper fluid made for summer temperatures can freeze in the winter which destroys your windshield wiper fluid lines and pump. Be careful!

If you notice your windshield wiper fluid disappearing without much use, there might be a leak. The reservoir can have cracks which were caused by previous accidents. There can also be leaks on the lines that transport the windshield wiper fluid from the container to the windshield. Get the system checked out by a professional if you think something is not right.

How to check the transmission and differential oil levels

To be honest, you won’t be checking these oil levels by yourself. Some cars have dipsticks for checking the transmission oil, but the majority does not. This means a mechanic has to do it for you. What you do need to know and do is replace the transmission and differential oil based on the interval predicted by the manufacturer of your car. Oil in the transmission and differential is the key part for the proper functioning of these components. It keeps everything lubricated and running smoothly. And you don’t want your transmission to fail, trust me. Replacing the oil is much cheaper than rebuilding a transmission.

What you need to know

  • Learn about the transmission and differential oil change intervals. And follow those intervals.
  • Check for any oily leaks underneath your car. They could be from the engine, transmission or the differential. In any case, have your car inspected immediately.
  • If you hear any weird hard noises and sounds coming from the transmission or the differential, have it inspected as soon as possible.
  • If you bought an older car with unknown service history make sure to have your mechanic check out these fluids. Check out the guide for buying a used car.

High fuel consumption

I’m sure anyone behind the wheel of their car knows how to check their fuel. Its the most annoying thing about your car. Observing your fuel consumption can actually help you diagnose certain things wrong with your car. Sudden high fuel consumption might indicate faulty sensors or other components. Here is what you need to know.

  • Bad spark plugs. Having bad spark plugs will cause your car to misfire and use more fuel which won’t burn up. Your car will start running badly once it starts misfiring.
  • Dirty air filter. Your car needs a source of air in order to function properly. If it does not get the air it will burn more fuel to maintain the same performance. Replace your filters regularly.
  • Bad oxygen sensors. Your car is constantly calculating the right mixture of air and fuel in order to combust properly inside the combustion chamber. If your oxygen sensor does not give the correct reading the car will automatically inject more fuel. This means your fuel consumption will be unusually high.
  • Tyre pressure. You would be surprised at how much your tire pressure affects fuel consumption, therefore, make sure your tires are properly inflated. Check the users manual to see what the right amount of tire pressure for your car is.
  • Extra load and weight. Don’t be surprised if your fuel consumption is much higher while carrying more weight in the car.


You now know how to check your cars essential fluids. Knowing this will ensure your car runs smoothly for a long time. That is why they are essential fluids!