Engine coolant isn’t something that is readily on most driver’s minds. Most don’t know how it works or that antifreeze is a component within engine coolant. However, most do know that if you don’t have enough engine coolant in your vehicle you are in for a big problem. Engine overheating can lead to some serious repairs, but you can avoid this issue by thoroughly vetting the integrity and volume of the coolant in your car.

So how much engine coolant, or antifreeze does your car hold and how full should it be? It will vary from vehicle to vehicle, but you want to keep you coolant levels topped off to the max fill line at all times. Most cars have 5 liter engine coolant tanks. You can buy engine coolant in bulk or by the 1 liter however, if you are topping up a reservoir that isn’t empty, use the same brand of antifreeze as last time. Different coolants can mix to produce dangerous chemicals that can cause engine damage.

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Engine coolant should be drained from the radiator and replaced entirely every 5 years or 100,000 miles on average.

Engine Coolant Volume


You can easily identify the engine coolant reservoir by looking for the brightly colored lid. In most vehicles it is yellow and has some form of warning o the car warning you that this compartment is pressurized when the engine is hot. It is important to only open it when the car is completely cool. You should be able to check your fluid level just by looking at the compartment as it is a translucent plastic and inside you’ll find a brightly colored liquid.

For specifics on where your car’s coolant reservoir is, we encourage you to check your owner’s manual which should have some form of visual representation of the location for your make and model. You can also find this information online by utilizing a simple Google search.

How to Check your Engine Coolant Level


There are three common varieties of engine coolant: they are inorganic additive technology, organic acid technology and finally hybrid organic acid technology.


This solution is outdated and is less superior than its competitors nowadays. As there are now more effective options on the engine coolant market you typically only see inorganic additive technology in older vehicles. 

If your car uses this type of engine coolant it is important that you stay on top of flushing your system and replacing your coolant.

Inorganic additive technology coolant must be changed every 24,000 miles or two years, whichever comes first. This is far more frequent than newer coolants that are on the market.


The next coolant we are going to discuss is much more with the times and requires far less maintenance and upkeep. It is increasingly popular in vehicles newer than the year 2000.

Organic acid technology coolant, which is widely used by General Motors, only needs to be changed every five years or 150,000 miles! That is a remarkably long length of time that you can go without replacing your coolant. This saves these car owners time and money involved with maintenance procedures.

This variety of OAT coolant is traditionally orange or red in color.

It is derived using fully neutralized organic acids and azoles and these are the components that make the fluid anti corrosive. This is also where the substance received its name.


Finally we have Hybrid Organic Acid Technology which is a slight variation of Organic Acid Technology. Both of these coolants have essentially comparable replacement cycles 

How To Top Off Your Car’s Coolant Levels

Most car owner’s are capable of topping off the coolant in their car. It is a simple process that just about anyone can do. The most important thing to remember is to NEVER touch the coolant reservoir when the car is hot. The compartment becomes pressurized and will shoot out molten hot liquid. Once the car cools down it is completely safe to open the cap and top off the fluid. Here are the steps you should take:

Start with the right coolant — As we discussed in the section right above this one, there are different varieties of engine coolant and your car will take one in particular. In addition to making sure your car is getting the right coolant, some coolant types should not be mixed with others and can cause severe chemical reactions if mixed. Check your owner’s manual to verify the type of coolant your car takes.Let the car cool off completely — You risk severe burns from hot engine coolant if you do not let the car cool of completely. Follow the instructions for diluting concentrated coolants — Some coolants are sold in concentrated form and will need to be diluted before being added to the coolant reservoir. It’s important to check the coolant label found on the container for instructions on this. In addition to concentrated coolants, some engine coolant is sold in a ready to use format and requires no diluting. Remove the cap and funnel in the coolant — After allowing the engine to cool completely, remove the cap and add in the new coolant to the reservoir. Do not overfill the tank as this system becomes pressurized when the car is hot and needs the extra room for expansion. Replace the cap — When you have finished filling the tank simply replace the cap. Be sure it is put on tightly and the reservoir is sealed.

A Brief Introduction On How The Cooling System Works (If You Care)

Combustion engines found in cars use energy from controlled engine explosions to propel them forward. However, the typical combustion engine produces twice as much energy in heat as it does in energy used towards forward motion. 

If this heat is not displaced of properly it can quickly destroy an engine. The job of your car’s cooling system is to release that excess heat in a way that is safe for you and your vehicle. Most modern vehicles use what is called a liquid cooling system. In this design, a water pump circulates coolant through your engine using plumbing and hoses to cool off the hot parts of your car’s engine. 


The now warmer (really freaking hot) fluid is then pumped into the radiator which works to cool the fluid back down using the ventilation and air flow from the front of your vehicle. The fluid is then recirculated into the hot engine to cool it down further. The process repeats continuously as the vehicle drives.

Your engine has a thermostat that measures the temperature of the coolant in the car. When your car is cold the thermostat will bypass the radiator and send the fluid directly back into the engine until the engine is hot and is readily heating the coolant.

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Why Cars Have Issues With Overheating

Typically when your engine overheats it is most likely caused by faulty or old engine coolant. The controlled gasoline explosions within the average car’s combustion engines is pushing 500 degrees and this is far too hot for most of the engine parts. 

If there isn’t enough coolant or the coolant is old and not functioning properly it may get hot enough to boil. Any boiling liquid is incapable of taking on any more heat until it becomes a vapor.

If the engine coolant starts to boil it is no longer effective at cooling down those metal engine parts that are being exposed to those scalding hot temps. When that metal heats up past a certain temperature a number of things can happen and none of them are a positive for your car. 

Typical repairs after an engine overheats include warped cylinders, cracked head gaskets and busted water pumps. The repairs average about $700 to fix just one of these issues. That is why it is imperative to ensure your engine coolant is not old and deteriorating.