The coolant in your engine has several very important functions. Even though it's called coolant, it manages temperatures at both extremes. Because coolant contains antifreeze it lowers the freezing temperature in your engine so that your engine can still function in cold weather without you having to worry about anything being frozen inside your car.
On the other end of the temperature range it is able to raise the boiling point of water which allows the coolants to carry heat away from your engine so that it can function at the optimal temperature. Without coolant doing its job, your engine would quickly overheat and seize up on you, potentially irreparably.
The 3rd function performed by coolant in your vehicle is an anti-corrosion function. In addition to its ability to maintain temperatures, coolant has anti-corrosion agents added to it. As it flows through the system it prevents rust and buildup from forming inside your radiator and other components. This can prevent coolant from leaking out so that it can continue to do its job and you don't have to worry about your engine overheating and seizing up on you.
As you can see, without coolant working properly in your engine you're risking some potentially serious damage. And that's why a coolant flush is necessary if you have a problem with the coolant in your vehicle. So how exactly do you know that there's something wrong with your coolant and that you may need a flush in the first place? Let's take a look and see what can go wrong, and what you can do to fix it.
Is a Coolant Flush Really Necessary?
A coolant flush is some routine maintenance that can help your coolant system keep working smoothly and efficiently. It definitely doesn't need to be conducted as often as some other types of similar maintenance in your vehicle, however. For instance, you will likely need to do an oil change more often than you will need to do a coolant flush. But that doesn't mean a coolant flush is entirely unnecessary. Some drivers may feel that simply topping off coolant when it gets low is good enough to keep things working, but that's not always the case. There are occasions when a coolant flush is the best course of action.
Over time, coolant will end up breaking down and performing more poorly. As it heats up and cools down repeatedly again and again during the process of performing its function in your vehicle, the chemical agents inside of it that allow it to take heat away from the engine and prevent corrosion are going to fail. As well, they're going to pick up dirt and debris. While this process may not be fast, over the course of many thousands of miles or many years this build up in your coolant lines can end up clogging your radiator and leading to an overheating engine.
Various components attached to your cooling system all bring with them expensive repair bills if they go bad. Heater core replacement may end up costing you well over $600, upwards of $1,000 in some cases. Replacing the radiator in your car could be anywhere from $300 to $1,200. And if your engine overheats badly enough, damages or replacement could cost well over $4,000. For that reason, you should definitely take the idea of a coolant flush seriously because the relatively low cost and inconvenience of coolant flush is definitely preferable to those big repair bills.
Although your owner's manual will tell you exactly when you need to have your coolant replaced in your specific model, a standard rule of thumb is that you should have your coolant flushed every 100,000 miles, or every three years.
There are a handful of benefits that come with getting your coolant thoroughly flushed rather than simply topping it up with new fluid if you have a problem.
Cleaning Out Debris: Coolant flushes are able to get rid of all of the sludge, scale, rust and other debris that may have built up in your coolant system overtime. All of these reduce the performance of your cooling and can potentially cause damage in the various parts of your cooling system.
Better Performance: With fresh, clean fluid in the lines you're going to have improved temperature control and corrosion resistance through the entire system. That means your radiator, your engine, and your heater core. Adding new coolant when your levels are low will assist in this, but a full coolant flush ensures that no old, contaminated fluid remains in the lines.
Better Lubrication: When you get rid of the old fluid it will assist in allowing your entire system to perform in a more efficient manner by putting less strain on all the moving parts. This includes everything from your radiator to your water pump. When they're able to move more smoothly because they're better lubricated, it means they're going to last longer as well.
Peace of Mind: This is one not everyone thinks of when they buy a new car, or in particular a used car, but knowing exactly what's in your vehicle can go a long way towards maintaining it. When you buy a used car, for instance, you don't actually know the quality of the coolant that is currently in it. Flushing the system and adding new stuff puts that knowledge back in your hands and gives you the peace of mind that you know how long it's expected to last and how it performs. You can take a lot of the guesswork out of the future of your vehicle.
How Much Does a Coolant Flush Cost?
Getting your coolant flushed is not an expensive job. You should never have to pay over $100 to get your coolant flush, and typically you should be looking at a cost of around $50. This will depend to some degree on the make and model of your vehicle, and also where you take it to get the job done.
How Do You Know When to Flush Your Coolant?
As we said, a standard rule of thumb is that if you were driving with the factory coolant in your vehicle you should probably get it changed by about 100,000 miles. Beyond that, getting it flushed every three years is a good idea. Of course, there will also be some signs and symptoms you can be on the lookout for to let you know that your coolant has gone bad and you need to get it flushed sooner.
Your Car is Running Hot
It's no surprise that if you have a problem with your coolant in your vehicle then your engine is going to start running hot. You'll notice the temperature gauge is heading up into the red zone if you have a problem with the coolant circulating through the system. If it just happens one time it may be not a big deal, but if you're noticing that your car is constantly running hotter than normal, and especially if the needle on the temperature gauge is hitting into that red danger zone, then you almost definitely have a problem with your cooling system and you're going to need to get it looked at as soon as you can. Your engine cannot operate at high temperatures for very long, and the longer it does so the greater the risk of damage and high repair bills that you're going to face.
For those who have never experienced it before, coolant has an unusually sweet odour to it. Antifreeze is made of something called ethylene glycol. Ethylene glycol has a noticeably sweet odour that can be very enticing to animals and even some people. There have actually been cases of people putting ethylene glycol in wine to cut costs and defraud consumers. Of course, ethylene glycol is also extremely toxic, so you never want to get exposed to this or let any animals or children get near it either. If you're noticing that sweet smell in the cabin of your vehicle, maybe it's blowing in through the vents, or you just experience it while you're driving that is a good indication you have a leak somewhere in your coolant system. This could be caused by the coolant degrading so much that it's eating through some lines or gaskets and causing the leak. You should have your coolant system inspected, any broken or damaged parts replaced, and then new coolant added after a flush has cleaned out the lines.
The coolant in your vehicle is probably either green or orange in colour. If it's badly contaminated it may become a muddy brown colour, or even black. However, if you're noticing the green or orange fluid leaking out from your engine compartment then that's an obvious sign that you have a problem. If your coolant levels are low, then you'll be unable to properly cool your engine and you will end up with those serious damages that we mentioned earlier.
Coolant Light Is On
Just like you have a check engine light on your dashboard you should also have a light that indicates you have a problem with your coolant levels. When it goes off, you can simply pop the hood of your vehicle and take a look at the coolant tank inside your engine bay to see how the levels are. If you're noticing they’ve dipped below the minimum, you can top it up to see if that will fix the problem. Make sure you're using the exact same kind of coolant that is in the tank already because if you mix the wrong types of coolant together you can actually cause them to create a jelly-like substance that will clog your radiator and cause even bigger problems.
If after topping up the levels you notice that they're going low again, you have a leak somewhere in the system that will need to be addressed.
The heat in your vehicle is part of the cooling system and it diverts the heat that is absorbed from your engine through the heater core and then back to the radiator again. If you find that when you turn the heater in your car on, no hot air is blowing from the vents in your cabin, this could be caused by a problem with your cooling system. Although there are potentially a few reasons why your heater won't work, if the coolant is not able to properly absorb the heat from the engine and then run it through the heater core in the cabin of your vehicle, that could be a sign you have a problem with the coolant in your vehicle.
What Happens if You Don't Flush Your Coolant?
If you don't actually get around to flushing the coolant when the system needs it, over time you're going to cause some serious problems for your car. Coolant has corrosion inhibitors in it that will degrade as the coolant degrades. That means the insides of your radiator, and your heater core, will start to corrode. That corrosion will flake off and contaminate the coolant as it flows through compounding the problem. That could end up causing your radiator to clog, and of course lead to your engine overheating. You can potentially damage your radiator, your heater core, and your engine as a result. If it gets bad enough, you may end up looking at several thousand dollars worth of repair bills to fix the problem.
The Bottom Line
Coolant flushes don’t need to be done anywhere near as regularly as something like a full oil change, but they're definitely necessary to maintain the overall integrity and proper functioning of your cooling system and your vehicle as a whole. You can only add new fluid into old so many times before you have to replace everything to properly maintain the functioning of your coolant. Always check your owner's manual and follow the guidelines that it establishes for how often you need to change your coolant, and if you notice any symptoms of a bad cooling system get them checked out as soon as you can to prevent some serious damages that could occur down the road.