Ever experienced a radiator leak? Just a distinct smell, with leakage, powerful enough to ruin your engine? We all have undermined that issue, at least once, with that “I’ll get it fixed later” attitude.

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Do you know why most of us don’t act immediately? Because we feel that it can only be done with professional help and that we can’t fix the leakage issue. Well, with this blog post, we aim to change that notion.

Stick with us as we uncover everything about coolant leak, from verifying symptoms and understanding pain points to finding and fixing a leakage. It’s time you put your DIY skills to use and get working on the problem that has you driving up the wall.

Coolant leak: Symptoms and causes

What is a coolant leak?

Your engine coolant or antifreeze is what regulates the temperature in your car. It helps your vehicle perform well and for fuel economy. It so may happen that sometimes the coolant may leak due to varying factors depending on one’s usage. The leak can occur anywhere in the cooling system and is usually very easy to identify since you will see it dripping from the component. It also has a very distinct odor and color that makes it easy to locate coolant leaks in your car. 

Symptoms of coolant leak

Your car is equipped to give out signals when it is damaged. When there is a problem, especially one like a coolant leak, there are many symptoms you can look out to help you identify the problem. Keeping a regular check for these will help you root out the problem in its nascent stage itself. A coolant leak will give out the following symptoms:

Puddles of coolant

One of the most obvious and easiest ways of checking for a coolant leak is to check for puddles under your car after you’ve parked. The coolant fluid is usually of lime-green, orange, pink, or blue-green color, making it plain to see. It is one of the first indicators of a coolant leak. The puddle gets accumulated under your parking spot after it has been still for a few hours. The colored fluid is nothing but the coolant fluid that has escaped. 

The wet radiator areas

You would notice some sort of residue on your radiator that can indicate a coolant leak. Since the coolant fluid can easily escape, it can leave your radiator feeling wet. If a sweet smell accompanies the wetness, you can be sure that a coolant leak is causing the residue. The distinct light color of the coolant fluid will immediately help you identify the problem. 

White smoke

White smoke in the exhaust is another indicator of a coolant leak. When the coolant leaks and escapes onto the engine, the engine’s heat instantly evaporates the fluid, leading to white smoke. Having this smoke appear could be dangerous; hence, we should take care of it as soon as it’s found. Keep your eye out for any smoke that can tell you if you have a coolant leak or not. 

Bubble in the radiator

Bubble in the radiator screams trouble. When the combustion gases force their way into the cooling system, it causes a coolant leak. First, you must inspect your vehicle to find the bubbling in your radiator. Bubbling could also mean a crack in the engine or head gasket, so look for more signs to determine whether it’s just a coolant leak or not. 

Rust and discoloration of the radiator

The toxic chemicals in the coolant fluid, over time, can cause your radiator to rust. The fluid upon leakage can fall on the hot engine and evaporate, leaving a residue that can later turn into rust. The discoloration and rusting of the radiator can help you determine that your cooling system is faulty. When you inspect your car, the discoloration or rust can easily give the coolant leak away. 

Coolant warning light

The low coolant level in the expansion tank will instantly illuminate up the coolant warning light if your car has that feature. Sometimes, the leak may evaporate even before it has a chance to drip. But the minute its fluid decreases, your car will let you know about the damage. Sometimes even if the light is on, your vehicle may appear to be running fine; however, it is not advisable to be driving around with the leak for too long.

Causes of coolant leak

The first step towards fixing a coolant leak is to identify the causes. Depending on your vehicle and usage, the cause of a leakage may vary. Cause usually leads to the solution as well. Knowing the various possibilities behind why your car has a leakage can save you time and money. Here are few general reasons for a coolant leak: 

Blown head gasket

This is one of the most common reasons for a coolant leak. Head gasket performs a crucial function for vehicles. First, it acts as a closing between the engine block and the cylinder head. It also helps to ensure there is no leakage between these parts. With the head gasket intact, there’s maximum compression in the engines.

Now, back to how the blown head gasket leads to a coolant leak. The head gasket comes in contact with water, coolant, oil, fuel, and exhaust gasses. When the head gasket is blown, it won’t be able to keep coolant in place, thereby, causing a leakage.

Radiator corrosion

Over time, the radiator and hose connection collects sediments which rusts. This rust leads to holes throughout the radiator, which leads to damage and forcing the coolant to leak. Besides, since the radiator is usually heated, there is a higher chance of it wearing down quickly. This wear can also cause a hole in the radiator. With this hole, the coolant will begin to leak. Therefore, it is important to ensure that your radiator is properly cleaned from time to time to avoid this mishap. 

Crack in the cooling jacket

Even the smallest crack on the engine block or cylinder head can spell doom for your cooling unit. Most of the time, the constant change in the temperature from hot to cold can also cause a crack in the cooling jacket. A combustion chamber leak in the cylinder can cause the oil to dilute with the cylinder walls, thus causing damage. 

Leaking Automatic Transmission Fluid (ATF)

The Automatic Transmission Fluid (ATF) oil leakage can cause coolant leakage too. Since the ATF oil cooler is routed through an oil cooler inside the radiator system. When ATF is leaky, coolant can enter the transmission lines, pollute the fluid and affect your engine dramatically. This leads to internal leak. Watch out for red or brown drops of oil in the coolant that can indicate the problem. If ATF oil leakage is causing the coolant problem, there’s a need for you to replace the entire radiator. 

Hoses connected to the radiator not properly sealed

Hoses are connected to the radiator, heater core, and water pump. Coolant also passes through these hoses, and thus they need to be in top condition to avoid any leak. Overtime, your hoses get brittle as a result of wear and tear. In light of this, you will find the hoses are either not connected well or have cracks. With this happening, the coolant is likely to leak from these areas.

Making sure that you look after the maintenance of your hose is important to prevent coolant leaks.

Leaky radiator cap

One of the purposes of the radiator cap is to regulate the pressure to prevent system damage. When the pressure is excessive, it helps make the cap open to relieve pressure. Suppose the cap is stuck, pressure inside will be built, this leads to leakage. 

If your system is losing coolant constant and has been overheated, it’s quintessential that you pressure test your radiator. When there are no visible external leaks, the chances are that the problem persists internally. In such a case, you need to watch out for a weak radiator cap that is unable to bear the pressure and replace it. 

Professional tips: If you’re in a tough spot, you can opt for a cheap fix by using a cooling system sealer. A cooling system sealer, though temporarily effective, is designed to seal the leakers. After you realize that the leak is internal, using a cooling system sealer will help you with timely fixes until you find a better and effective solution. 

Common places that coolant leak from

Water pump

The water pump is one of the most important parts of your cooling system. Your car needs it to circulate the coolant between the engine and the radiator. It pumps the coolant from the radiator all around the engine and returns it to the radiator. This process is repeated continuously. A bad shaft seal can allow the coolant to escape out from under the water pump pulley shaft. Discoloration or stains will tell you if you have a coolant leak or not.

Reservoir

A coolant reservoir is a plastic tank that is attached to the engine and stores the coolant fluid. It helps regulate the flow of hot and cold. Since the hose is part of the system, it is bound to get hard and brittle over time, making the clamps on the reservoir loosen up. This allows the coolant to leak out and damage your cooling system.

Radiator 

This is the most commonplace for the leak to occur. Having an aluminum core, the leak may happen over any of the joints attached to the radiator itself. The vibrations loosen the hose around the radiator and thus cause the leak. The radiator’s core is also vulnerable to stone damage that weakens the radiator and causes coolant to leak. Moreover, the radiator is usually very hot and would have gone through a lot of temperature changes. Because the radiator houses the coolant, it is one of the places the antifreeze can leak from.

Hoses

The hoses serve as a connector between the reservoir, water pump, and other parts of the vehicle’s engine. Because of continuous usage, the seals of the hose can become slacked and not fit well. Not only that, but the hoses can also get punctured due to constant use. When these happen, then the coolant can start leaking from different parts of the hose. 

Head gasket

Identifying a leak at the head gasket can be difficult, but it is also most dangerous if the leak occurs there. Once the leak is at the head gasket, there is a major loss of the coolant and can cause quick engine damage. One of the significant signs to look for is white smoke coming out of the tailpipe. When the coolant enters the combustion chamber, it tends to burn and evaporate, which is not good at all. Note that even though the engine might feel warm, you’ll still be able to smell something sweet. (That’s nothing but antifreeze). 

How to find a coolant leak?

There are usually two ways of finding a coolant leak – using a pressure tester and not using a pressure tester. 

What is a pressure tester? 

A pressure tester is a tool that uses the vacuum-pressure gauging mechanics. With fitting attached to the radiator, pressurizing the tool will help generate ratings. These ratings will be visible on your engine’s radiator cap. For example, if your radiator cap says 10 pounds, then you pressurize your radiator to 10 lbs. If it can handle the pressure without any leakage for 10-15 minutes, your coolant is working fine. 

Finding coolant leak without using a pressure tester

You can also identify the leak without using a pressure tester. Start this way by taking the top off your cooling system, tightening your radiator cap, and turning on the engine. Once it reaches a normal operating temperature, you can turn on the air conditioner to check how it holds off additional load to the cooling system. After you do that, you can check your system for any leakage. 

Sometimes, you may not be able to see the leakage, but that does not mean that there isn’t any. Your car may have an internal coolant leak. Here’s how you can differentiate between the two. 

External leak

An external leak is when the fluid escapes and drips/seeps out of the cooling system. Diagnosing an external coolant leak is easy. Park your car over a spot for a few hours. If you find puddles on the floor mats of either the driver’s/passenger seat under the car. Locating a leak with your eyes is a sure-shot way of knowing that is what is causing damage to your cooling system. 

In case that you do not see the puddles but your reservoir level is low. Check for other signs of leakage. Take a look around the radiator cap and throughout the engine system. If you see leaking around the cramp, then tighten it with a socket wrench or screwdriver. In case that you do not see any leakage at the cap or other areas, check for the smell inside the system. Finding a sweet smell from the engine may have resulted from the heater core or internal leak.

Internal leak

Internal leaks are simply leaks where the fluid does not escape the cooling system – quite literally the opposite of external leaks. Using a pressure tester is advisable to identify an internal leak since it is very likely that the internal leak may go through the engine, which may cause it to evaporate. However, when it does that, the residual white smoke can often be seen, which is a huge indicator of a coolant leak. 

How to fix a coolant leak?

After identifying and locating, it is now time to fix the leak. Depending on where your leak has occurred, you can use various methods of fixing it. Some common ways of doing them are: 

• Installing a new radiator cap since an old or worn-out one will not hold the pressure causing the coolant leak.
  
• Replacing the hose with a new one will instantly make sure that the leak is secured. 

• Suppose the leak is caused due to the radiator being subjected to corrosion, debris damage, or even minor impact. In that case, you will have to repair the radiator completely to fix the leakage.
  

Stop-leak products 

While fixing a coolant might seem difficult, that’s not the case. Once you’ve identified the symptoms and root cause for the leakage, you can fix a coolant leak using stop-leak or sealants. These products are readily available in the market and can help you save a good chunk of money.

Note: Using stop-leak is just a preventive measure and not a comprehensive solution. For instance, more significant leaks that cause puddles beneath your car need more aggressive fixing. 

Testing your repair

From the outside, all may seem well, but until and unless you test out your repair, you won’t know whether it is truly complete or not. Don’t forget to take your car out for a test drive, preferably around your neighborhood. In case anything is amiss, you can call someone for help. If no issues occur, then your cooling system is working perfectly fine, and the leak has been fixed. 

Tips: When testing your coolant post-repair, you should make sure to check your radiator and even flush the same to identify if there is any leakage. Examine everything in-detail and scrutinize each aspect to prevent future leakage. 

How much does it cost to fix a coolant leak?

The cost of fixing a coolant leak depends upon the extent of the damage and where the leak is located. If it is a simple hose problem, it can cost you $40 to fix it. Replacement of the entire radiator can cost up to $300, which is a steep amount for anyone to bear. Make sure you recognize and fix your coolant leak as soon as you identify the problem and stop it from becoming worse. 

FAQs

1. How long can you drive with a coolant leak?

It is recommended to get your coolant leak fixed as soon as possible. However, if you cannot do it due to some emergency, you can go for a few days with the leakage. Ignoring the early signs of a coolant leak can very well get you stranded on the side of the road so keep a check on the cooling system of your car. 

2. How long does it take to fix a coolant leak?

It usually takes about 20 minutes to an hour to fix a simple coolant leak unless it is severely damaged. Leaking the water pump or head gasket would take longer. It may take you one or two days depending non how bad the damage is and what needs to be done to fix it.

3. Is it okay to smell coolant?

Coolant has a very distinct, sweet smell that one can recognize easily – helping them identify the coolant leak. The sweet smell of coolant is from antifreeze, which contains liquid alcohols like ethylene glycol, propylene glycol, and methanol. These types of chemicals are very poisonous and hazardous. Smelling coolant for a long period is discouraged as the toxic chemical can prove to be harmful. 

Conclusion

A coolant leak is one of the signs that suggest your vehicle is now getting old, and you need to take a little more care of it to ensure it lasts longer. For DIYers or home mechanics, it is crucial to know everything before beginning with the repair. Make sure you’re aware of what you’re getting yourself into, and don’t forget to test your car once you’re done fixing it.