One element of your car that is essential for optimal performance and for averting potentially significant issues is the cooling system. A car that isn’t adequately cooled stands the danger of overheating, which can result in exorbitant maintenance costs, significant damage, and malfunctions.
The last thing you want to happen is to need to replace your entire engine due to substantial damage caused by running it too hot.
Maintaining the efficiency of your cooling system is consequently crucial, and as a result, you must watch out for the issue of air in cooling system. When this occurs, your system’s capacity to maintain a stable temperature is significantly reduced.
Your car’s engine might suffer significant harm from a malfunctioning coolant system. As soon as you spend all of your funds on repairing the engine parts, you will have a huge hole in your wallet.
Therefore, to maintain an engine performing at its best, it is crucial to have a functioning and suitable cooling system. But how can you know whether the cooling system’s air is faulty?
A cooling system has numerous crucial functions. To begin with, it disperses surplus heat accumulation in the engine to avoid overheating. Second, this mechanism keeps the engine’s operating temperature constant.
But occasionally having air build up within a coolant system is one of the typical problems. The engine suffers severe faults as a result. How can you know whether the cooling system has air? Even though the warning indicators are quite obvious, some owners have trouble seeing them.
How Is the Cooling System’s Working Mechanism
A cooling system has many parts, including an engine, a radiator, a water pump, a heater core, a thermostat, coolant lines, and a radiator. Knowing how to determine whether air is in the cooling system is crucial since it performs one of the most crucial tasks within the vehicle.
Bleeder valves can be found on the top or front of the radiator. As soon as you open it, air will start to flow out of the cooling system.
The process is as follows:
- An impeller that controls the coolant flow is part of the water pump. It has a windmill or fan-like appearance, and the serpentine belt turns it.
- The coolant jacket of the engine, a complicated network of passages along the engine block, is where the coolant travels. Heat is absorbed by the coolant, which transfers it to the heater core outside the engine.
- The heater core, a miniature radiator used to warm the vehicle’s interior, is located inside the car. The flow of hot coolant through the heater core is maintained via a valve. The coolant travels to the radiator through the pipe.
- Simple coils of a long tube called a radiator, are compact and short. The coolant’s temperature is lowered due to heat being dispersed from the coils by the air. The hose transports the cooled fluid to the water pump after passing through the radiator. This cycle never ends.
Which are the Common Common Air In Cooling System Symptoms?
There are a few indications that there is air in cooling system that you can be on the lookout for, which can help you choose where to hunt for a solution.
When there is air in cooling system, steam pockets form in the line that function nearly like plugs to stop the coolant from flowing. Because the coolant is either unable to flow through normally or travels extremely slowly, your engine overheats as a result.
The engine will cool down once the air pocket can be cleared out of the way and the coolant can once again begin to function. Unfortunately, until it is addressed, this will keep happening. Every time the coolant system is exposed to the open atmosphere, you must thoroughly cleanse the system.
1. Overheating Following Repairs
There’s a good chance that something is either cracked, loose, or improperly secured and that has resulted in the air in the line if your car hasn’t had any issues with overheating before taking it to the shop for some work, especially if you had something like the water pump, the radiator, the heater core, or coolant hoses looked at. If you’re now experiencing overheating in your engine.
2. Sporadic Overheating
This occurs when your car begins to overheat and then seems to stabilize on its own without any intervention from you to stop or fix the issue.
This happens when air bubbles cause an overheating condition, and coolant then flows down the pipe to bring the temperature back down to the proper level. As the coolant’s air cycles through the pipes randomly, this will keep happening.
The air in cooling system might become caught, which can cause the vehicle to overheat. The sensors can’t accurately indicate the temperature because of the air bubbles inside. The fan and cooling system are not activated when the sensor detects a lower temperature.
But there is also another thing to think about. The thermostat won’t open if there are air bubbles within until the temperature is high.
The basic goal of a cooling system is to regulate fluctuations and keep the inside of a car at a constant temperature. You may identify a malfunctioning system by its unpredictable temperature spikes.
The coolant is poured into the radiator by Fir0002 / GFDL 1.2 The pump will draw air from the expansion tank if the coolant level falls below the necessary minimum levels as a result of leaks or water evaporation.
3. The Vents Aren’t Heating Up Well
You’ll notice that sometimes the air blows warm and other times it doesn’t if you’re attempting to keep your car warm since it’s chilly outside. This is a sign that there is air in cooling system.
One of the many indications that there are air pockets in the coolant system is a broken vehicle heater. There won’t be any heat coming from the vents when you turn on the car heater.
The air could not be forced out because of the air bubbles. The hot fluid cannot enter the heater core because of the trapped air.
4. Changing Idle
There’s a significant probability that you have air caught in your coolant line if your car appears to have issues at idle that are inconsistent with the harsh idling that you would experience from engine misfires, such as it seems to idle up and down randomly.
5. White smoke emanates from the exhaust
The most typical indication that a bad head gasket let coolant into the combustion chamber is this. Additionally, the cooling system can be reached by the exhaust gas from the cylinder block, allowing the cooling system to cool the engine.
6. Indications of Coolant Leakage
Wet spots and dried white smudges on pipelines, engines, reservoirs, and other nearby regions are signs of coolant leaks that cause air bubbles to develop.
7. Water Gushing Inside the Dashboard Can Be Heard
Many customers say that the dashboard is making an odd water-gushing sound. The air is first trapped inside the cooling system. The coolant rushes through the heater core when the vehicle is started, but not before making that interesting gushing sound. However, how do you eliminate it?
Always make sure that the radiator is full of coolant. The system must be cleared of any air. Some cars include particular valves for this reason, but we’ll get to that in a moment.
Following our study of the reasons and signs of air in cooling system of the engine, we will now go further into how to identify these air bubble sources on those vehicle components.
Why Does Air Develop In the Cooling System?
In a healthy engine, the coolant expansion tank squeezes out air entering the cooling system; but, in unhealthy systems, air can accumulate and restrict coolant flow.
A weakness in the system’s tightness is the most frequent reason for engine cooling system airing. Antifreeze causes pressure drops in the circuit by expanding as it warms and contracting as it cools.
A two-way valve on the radiator or expansion tank cap can be used to align them. It releases more pressure into the environment during times of intense warmth, and it draws air back in during periods of cooling.
The air is seeping into the cooling system either as a result of the valve’s malfunction or as a result of its prolonged suction through other nodes.
What are the Main Causes of Air In Cooling System?
There are a few ways that air might become caught in your car’s cooling system. These are all things you may watch out for to see whether there is air in the lines and whether it has to be filled with blood to fix the issue.
1. A Malfunctioning Cylinder Head Gasket
A failing head gasket or one that isn’t properly tightened allows air to enter the cooling system when the pressure in the system lowers. Additionally, exhaust gas can enter the cooling system.
2. An Obstructed Thermostat
A broken thermostat prevents air stored in the coolant from escaping into the coolant expansion tank and ultimately into the atmosphere.
3. A Faulty Water Pump
If the water pump leaks, airlocks will occur because air is drawn into the cooling system. Even worse, a worn-out pump is unable to provide the necessary pressure to release air bubbles into the expansion tank, making the situation worse.
4. A Damaged or Clogged Expansion Tank Cap Valve
The formation of air in cooling system is another potential consequence of this issue. The broken valve prevents extra air from being released when the antifreeze is heated and the circuit’s pressure builds.
If the valve does not work properly, air cannot enter the tank during cooling, increasing the possibility of suction in other areas.
5. A Leaky Heater or Radiator
Cracks in the heater and radiator might let cooled air in cooling system.
6. Low Amount of Coolant
If the coolant level drops below the required minimum levels as a result of leaks or water evaporation, the pump will pull air from the expansion tank.
7. Depositions on the Cooling Circuit’s Walls
The regular circulation of the coolant is disrupted, which prevents air bubbles from being expelled from the system, and deposits on the cooling circuit walls restrict its cross section and throughput.
8. Damaged Hoses, Pipes, and Seals
Air seeps into the cooling system when the pressure drops due to worn seals, warped pipes, or loosened clamps.
9. A Defective Radiator Cap
There is a potential that air is entering the line if the radiator cap isn’t properly shut. For the radiator cap to function correctly, it must be sealed and pressured. If the seal is not perfectly tight, coolant will leak and air may enter the line.
10. Improper Coolant Refill
If you’re replacing the coolant in the tank or if you flushed it improperly, it’s conceivable that air became caught in the system and has to be flushed out again.
Out of all the issues stated, this one is the simplest to resolve because nothing has to be fixed. All you have to do to guarantee there are no air bubbles is bleed the line and then carefully refill it.
How Can You Determine Whether There Is Air In Cooling System?
To determine whether this is the case, it is crucial to know how to detect air in cooling system. You may check to see if the cooling system contains air by taking the following steps:
The cooling fan of a radiator by Saud / CC BY-SA 4.0. The cooling system’s air may become trapped, which would make the car overheat. Because of the air bubbles inside, the sensors can’t provide an accurate reading of the temperature. When the sensor senses a lower temperature, neither the fan nor the cooling system is turned on.
1. Check the Radiator and the Pipes In the Cooling System
Watch out for any wear or cracks in their joints as well. Verify that the hoses are in good condition and that the clamps are firmly connected.
Small cracks may not enable coolant to flow when the pressure lowers, but they may let air in.
2. Check the Water Pump’s Functionality
Listen to engine sounds to detect coolant leakage. If the pump is operating correctly, you should be able to feel the liquid throbbing within the branch line heading to the radiator when the engine is running.
3. Inspect the Expansion Tank for Signs of Air Bubbles
When the engine is warm, you may rev it up to 3000 rpm and listen for air bubbles. Their presence frequently indicates an engine gas leak.
If the coolant level progressively drops and white smoke begins to emerge from the exhaust pipe at the same time, a cracked cylinder head gasket is extremely possible.
Air In Cooling System: How to Fix and Release Air from the Cooling System
If you are certain that your vehicle’s cooling system contains air, you must drain it to get the car working correctly once again. By bleeding the system, you are effectively eliminating the air pockets and avoiding overheating.
Additionally, you are preventing the numerous negative repercussions of an overheated engine, such as warping or cracking. It will cost you close to a lot to fix an engine that has been overheating for a long time.
A cooling system can be bled off the air in a variety of ways. The majority of it is based on the brand, model, and year of the car you’re driving. A component known as a bleeding screw or valve is included in some vehicles. This greatly simplifies the procedure.
The radiator’s front or top both have bleeder valves. The air in cooling system will immediately leak out as you open it. However, not every vehicle has that characteristic because they were not all made equal. To find out if your vehicle has one, consult your owner’s handbook.
As an alternative, you may jack up your car and let the air out. With this technique, the air pockets are forced to shut up because the radiator is raised above the rest of the system.
1. Using a Bleeder Valve or Bleeder Screw to Drain Air In Cooling System
Your life will be made simpler with a bleeder valve. If you have the luxury of utilizing a bleeding screw, follow these instructions to bleed air from the cooling system.
Step 1: Make a Solution of Antifreeze and Water
To make a solution, combine one part water and one part antifreeze. Fill the radiator with a small amount. Add the same combination to the coolant reservoir or overflow tank as well.
Step 2: Turn Off the Engine
Remove the radiator cap, turn the engine off, and then let the radiator drain itself. As the engine recovers to the proper temperature and begins cycling coolant, the procedure typically takes 15 to 20 minutes.
The coolant level will decrease significantly once the air has been forced out. You will hear or see air bubbles leaving the radiator, which may gurgle.
Car engine by Tennen-Gas / CC BY-SA 3.0. Air that enters the cooling system is squeezed out in a healthy engine by the coolant expansion tank, but in less-than-optimal systems, air can build up and obstruct coolant flow.
Step 3: Observe the Temperature
Watch the temperature gauge as the procedure progresses. If not quite normal, it ought to reduce near to normal. This procedure helps the system keep the engine cold for a longer period by distributing coolant to the radiator more evenly.
Step 4: Fill Again the Car Radiator
Refill the coolant reservoir and the radiator with coolant. As the air was the only thing filling them up to the top before, they could only be halfway filled. Make sure the coolant in your vehicle is not low.
Step 5: Replace the Old Radiator Cap with a New One
To keep the radiator in place, use the cap. This maintains the majority of the air outside the system, where it belongs. The car’s temperature gauge ought to be back to normal by this time. If the overheating keeps happening, another issue can be present.
2. Bleeding a Cooling System Without a Bleeding Valve
You will be able to bleed the system with a bleeding valve after you understand how to determine whether air is present in the cooling system.
In case your vehicle doesn’t have a bleed screw, you can try this technique. You must make sure the vehicle is cool for this exercise or risk hurting yourself.
Prepare the distilled water and coolant combination once again. Remove the radiator cap and fill it with the coolant-water mixture to the neck. Don’t forget to add some solution to the reservoir as well. Restart the engine while in that position.
Coolant will begin to flow into the tank once the vehicle achieves the proper temperature. Air will be gradually purged from the system as the coolant circulates through it.
Immediately after this, shut off the engine and let it cool. Fill the tank full with extra coolant. Squeeze the upper radiator hose just enough to make certain that all of the air has been removed from the cooling system.
Finish by putting the radiator cap back on and starting the engine to get it warmed up. Check to see if the temperature is maintained this time by giving your vehicle a test drive.
3. Draining Air In Cooling System Using Jack Stands
You must set up jack stands underneath your vehicle to completely drain away the air from the cooling system. Always make sure the engine and radiator are cold.
Lift the vehicle with a floor jack so that the radiator’s neck is above the engine. Cover the back wheels and use jack stands to secure the vehicle in place on either side. We advise slamming on the parking brake.
Similar to previous techniques, start the engine before removing the radiator cap and bringing the vehicle to the ideal temperature. Once the cooling system has been cleared of air, let the engine run for a while. The engine can then be stopped.
Once the engine has had time to cool, keep adding coolant until the right level is reached. If necessary, fill up the antifreeze and squeeze any leftover air bubbles out of the upper radiator tube. Bring the car down, replace the cap, and then drive it.
Your car should no longer contain any air or air pockets by this time. However, if the signs persist and you continue to have the same difficulties, take the car to repair since it may have issues that you are unable to fix. Your cooling system most likely has a break or crack somewhere that is enabling air to enter.
Cylinder head by Kauczuk / CC BY-SA 3.0. A damaged cylinder head gasket is quite likely if the coolant level gradually declines and white smoke starts to appear from the exhaust pipe at the same time.
What are the Ramifications of Air In Cooling System?
When the air becomes trapped in the cooling system, a vacuum is created, allowing atmospheric pressure to drive the fluid back into the system.
The insufficient liquid in the tank causes the cooling system to get air rather than coolant. The worst-case situation isn’t having the coolant level slightly below the ideal level, but it can cause the car to overheat.
Additionally, if there is an air bubble or pocket in the cooling system, it inhibits coolant from flowing to that area. The question that follows is, “What causes the creation of air pockets in the cooling system?”
Bleeding and refilling the antifreeze system may have caused it. Air can enter the system after the water pump has been changed or the cooling systems have had their coolant flushed. Even if the engine appears to be fully fueled, air pockets like that might cause it to overheat.
Air In Cooling System: How Dangerous Is It?
Air bubbles may first look harmless, but over time they can become quite dangerous. They cause the vehicle to overheat by accumulating heat inside the cooling system of the engine.
A warped head, a blown head gasket, a fractured engine block, broken pistons or valves, burst hoses, or a blown radiator may result from exceeding the safe operating temperature range.
Repairing Coolant Leaks
There are a few things you may do to fix coolant leaks if you detect them. Finding the leak’s source should be your priority. Once the leak has been located, it may be patched or sealed.
You’ll need to take the radiator off of the vehicle if the leak is in the radiator. Check the fins once it has been removed to make sure they are not twisted. If they are, straighten them out with a fin comb. Once the radiator has been fixed, you may reinstall it in the vehicle and add coolant to it.
You’ll need to remove and disassemble the water pump if the leak is there. Check the seals and gaskets to check if they have any damage. If so, you’ll need to swap them out. You may reinstall the water pump and add coolant once it has been fixed.
You’ll need to change the hose if one of the hoses is leaking. To begin, unplug the hose from the water pump or radiator. Then, use a pair of pliers to remove any clamps or fittings before cutting the old hose off.
The replacement hose should then be slipped over the fitting and fastened using clamps or fittings.
Once the leak’s origin has been identified and fixed, you can add coolant to the cooling system. Run the engine for a few minutes after starting it. After that, switch it off and check the coolant level. If necessary, add extra coolant.
Preventing Coolant Leaks
There are a few steps you may take to stop coolant leaks before they start. Checking your cooling system often for any indications of wear or damage is the easiest method to prevent leaks.
Additionally, ensure the hoses and clamps are secure and in excellent working order.
Making sure your vehicle is using the right kind of coolant is another technique to stop leaks. Consult your owner’s handbook or get the help of a professional if you’re uncertain about the type of coolant to use.
An engine, a radiator, a water pump, a heater core, a thermostat, coolant lines, and a radiator are just a few of the components of a cooling system.
Finally, be sure to follow the manufacturer’s guidelines while changing the coolant in your vehicle. By doing so, you’ll be able to stop the corrosion and buildup that might cause leaks.
It’s not unusual to experience air in cooling system of your car, but you should take care of it as soon as you notice a problem. As we previously stated, an overheated engine might result in significant damage.
The majority of people don’t believe an overheated engine can be all that awful, but if the engine’s cylinders or valves end up warping as a result of persistently high temperatures, the repair costs might reach $3,000 to $4,000 or even more. For something that might have been corrected far more easily, that seems like a rather expensive price to pay.
Depending on where you reside, having your coolant system cleansed by a professional should only cost you $40 to $50. The cost of solving the issue after it has arisen differs significantly from the cost of preventing it from occurring.
You don’t want to ignore this issue for too long and risk having it get worse and cost you a lot more money if you’re experiencing issues that appear to be caused by air in cooling lines. Get to a mechanic as soon as you can, or if you feel competent, attempt to handle it yourself using the techniques we’ve listed.
Jim Wicks is the founder of MotorVehicleHQ. With over two decades of experience in the automotive industry and a degree in Automotive Technology, Jim is a certified car expert who has worked in various roles ranging from a mechanic, car dealership manager, to a racing car driver. He has owned more than 20 cars over the past 15 years. Ask him about any vehicle you see on the road and he can tell you the make, model and year. He loves the aesthetics of all things cars, and keeps his vehicles in pristine condition.
In his free time, Jim enjoys getting his hands dirty under the hood of a classic car or taking long drives along the country roads. His favorite car? A 1967 Shelby GT500, a true classic that, according to Jim, “represents the pure essence of American muscle.”