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DIY Guide to Finding and Fixing Coolant Leaks in Your Car

If you’re like most people, dealing with automotive troubles isn’t the most attractive thing. As a result, it might be easy to dismiss early indicators of possible problems in the hope that they would go away, but this is never a wise strategy. Car problems do not go away, and if they include engine coolant leaks, even minor difficulties can soon escalate. 

Let’s see why a coolant is important for the smooth functioning of your car and what are some practical ways to find and fix tiny coolant leaks.,

What is a coolant?

Coolant is an engine fluid that regulates the temperature of the engine. It prevents the engine from overheating and freezing. The coolant is also called “antifreeze.”  

The primary job of engine coolant is to control heat from engine components and protect the engine from damage caused by overheating or freezing.

This coolant is a mix of antifreeze and water. It absorbs heat from the engine and expels it through the radiator.

The fluid behaves differently during the summer and winter. It keeps water from freezing in cold weather (hence the name, antifreeze) or boiling over in Dubai’s harsh conditions.

What is a coolant leak?

A coolant leak occurs when coolant exits the cooling system as a result of a leak or damaged components.

Coolant or antifreeze leaks can occur due to various factors, including a blown head gasket, damaged hose clamps, radiator hoses, or a damaged heater core.

As the coolant leaks, the coolant level in the radiator drops below the required level, potentially contaminating the engine oil, damaging the cylinder head, overheating the engine, or causing the engine to fail.

Symptoms of coolant leaks

1. Low coolant levels

The car has an expansion tank that stores more coolant in case the engine coolant level drops too low, and automatically refills it from the reservoir itself. Check the coolant level in the expansion tank. If it’s low, your coolant may be leaking.

2. Overheating Engine

When coolant leaks, air takes its place. Because air is compressible, the boiling point will drop, enabling part of the coolant to evaporate into steam. Air and steam are excellent insulators, preventing the cooling system from releasing excessive heat. If the temperature gauge is approaching the red zone or you see a temperature warning light, you may have a coolant leak that you cannot detect.

3. Puddle under the car

If you see a puddle on the ground or smell coolant in your vehicle, you have detected a major coolant leak that must be corrected before it causes serious engine damage. Look for a red, pink, green, or blue puddle under or within your vehicle, as well as residue on any component of the cooling system.

4. Bubbles on the radiator surface

Small bubbles on the radiator’s surface indicate that your vehicle may be leaking coolant. However, they could also indicate flaws in the head gasket or engine, so have your vehicle inspected by a specialist.

5. White smoke

White smoke coming from the exhaust pipe could indicate a coolant leak. This can happen when there is a crack in the engine block or another issue, such as a blown head gasket. These conditions can generate so much pressure that the coolant is driven into the cylinder, causing it to turn to steam each time the engine fires up.

6. Sweet smell

Another sign of a coolant leak is a sweet-smelling odour, which is frequently described as having a subtle metallic scent. When there is a leak, fluid can gather in the plastic housing at the bottom of the heater core, causing this odour.

If you smell a pleasant perfume emanating from your engine compartment, you should inspect the heater core and other cooling system components for symptoms of leaking.

How to find the source of the coolant leak?

As previously established, coolant leaks can occur for a variety of reasons. If your car’s coolant has leaked and you want to find out why, follow the steps mentioned below:

  1. Lift the hood of your car to get a nice view of the engine compartment.
  2. Now inspect the engine and look for any signs of coolant leaks. Do you see a light-coloured stain on the radiator or a liquid residue? Check the hoses and other components including the hose clamps and the radiator cap.
  3. If you see signs of coolant around the clamps or the radiator cap, there’s a simple fix – take out the screwdriver and tighten the clamps and the cap. However, if you don’t see any signs of coolant, the source is internal and you will have to inspect the internal components of the engine to spot the source. 
  4. If the smell of antifreeze is strong inside your car, it is most likely that it is coming from the heater. Such types of leaks are hard to spot and fix as it is located behind the instrument panel. You will need to ask a professional mechanic for help.

Causes of a coolant leak

Coolant leaks can be caused by various issues, including a blown head gasket, a radiator cap leak, hose leaks, and many others. Let’s have a look at the causes of coolant leakage:

1. Leaky radiator cap

When you notice coolant leaking from the bottom of your vehicle, it could be the doing of a faulty radiator cap. 

When the coolant heated up, it overflowed from the radiator’s end. The radiator works based on pressure, which is stabilized by a cap. When the cap is not correctly fitted, pressure does not build up, resulting in coolant loss.

2. Damaged hoses

Hoses play an important function in the cooling system. They link the water pump to the engine, which in turn connects to the radiator. Coolant runs through the hoses which are located beneath the hood of the car. 

Over time, the hoses grow stiff and brittle. A fractured or damaged hose can result in a coolant leak.

3. Hole in the radiator

As we all know, an engine produces tremendous heat. As a result, automotive engine parts must survive significant wear and tear, as well as severe temperatures and pressures.

The hose weakens over time, allowing dirt and pollution to accumulate inside it. When debris comes into touch with the radiator water, it may cause corrosion inside the radiator. This rust may form a hole in the radiator, resulting in coolant leaks.

4. Blown head gasket

Your vehicle’s head gasket seals the gap between the cylinder head and the engine block. If the head gasket fails, coolant and engine oil could mix. You may also observe coolant leaking from the engine’s underside and dripping to the ground. In either case, a burst head gasket can be quite damaging to your engine.

5. A dysfunctional water pump

The water pump pumps coolant throughout the system. Normally, the pump is powered by a belt. The belt, which connects to the engine crankshaft, is susceptible to leaks and corrosion.

The water pump might be damaged by external factors, resulting in leakage. If the pump fails, the coolant cannot circulate correctly, causing the engine to overheat.

How to fix a coolant leak

The coolant or antifreeze is not difficult to repair. As previously noted, your radiator antifreeze may leak for a variety of reasons. Here are some different methods to help you fix coolant leaks on your own:

1. Replace the damaged hose clamps

Clamps hold all of the hoses in place. If a clamp becomes corroded, you must replace it.

  1. Let your car cool down then find the defective clamp. 
  2. You might have to dump the coolant into a bucket if you cannot reach it. 
  3. Remove the damaged hose and the old clamp then put on the new clamp and make sure it’s properly tightened down.
  4. Fill the radiator with fresh coolant and tighten down the cap. 
  5. Turn on the car and let it run until it reaches the correct temperature. 
  6. Look around and make sure there are no other overlooked leaks.

2. Replace the damaged radiator hose

As your car ages, the rubber and plastic tubes that supply the engine’s critical fluids can crack, break, and pop. 

You’ll undoubtedly observe a few coolant droplets on the ground, but they might quickly turn into a puddle. When that happens, you’ll need to swap them with new ones.

  1. Allow the car to sit and cool down for 5 to 10 minutes.
  2. Open the hood, then remove the radiator cap.
  3. Find the broken hose. 
  4. To reach the place where the hose is located, you should pour out some coolant. Drain the liquid into a bucket by placing it under the hose. 
  5. Now get to working and unscrew the clamps on either side of the hose. See if the clamps look damaged or worn out as sometimes the clamps are the culprits. 
  6. Now take out a new hose and fix the clamps to the new hose properly.
  7. Tighten the clamps using a screw.
  8. After filling the radiator with fresh fluid, tighten the radiator cap.
  9. Start the car and let it warm up. The replacement hose can now be tested for leaks. You’re finished if everything looks good!

3. Replace the faulty radiator

Keep in mind that radiator installation varies based on the car manufacturer, however, some processes will be the same.

  1. Allow the car to cool down before disconnecting the battery. 
  2. Drain all of the coolant from the system by withdrawing the plug at the bottom of the radiator. Make careful to dispose of the coolant correctly.
  3. Remove any tubes that link the radiator to the engine, and then remove the thermostat. 
  4. The fan installed on the radiator should be removed. 
  5. Remove the bolts that hold the radiator to the mounting bracket.
  6. Remove and replace the old radiator. 
  7. Reassemble everything in reverse, replacing any worn-out parts in the process. 
  8. Fill the radiator and start the engine to check for any additional leaks.
  9. If you are experiencing problems with your vehicle, including a possible coolant leak, you can have it tested, diagnosed, and remedied by contacting a mechanic today.

Why am I losing coolant but no leaks?

If you still can’t find the cause of the radiator coolant leak, examine your car’s coolant recovery tank. The indication is located on the side of the clear plastic tank. Inspect the coolant level; it should fall between the “min” and “max” marks. If it is, the leak is most likely unconnected to the coolant. However, if it is less than the minimum, it indicates that the leak is related to the coolant and requires repair.

How To Drain Coolant From The Engine Block

Fortunately, there are techniques to prevent engine coolant leaks. One of these techniques is a regular maintenance routine, which includes replacing the coolant in your radiator. Old coolant left in your radiator for too long might get corrosive and erode at the aluminium casing, producing a leak. As a result, draining and replacing coolant from the engine block regularly can save you from future problems. Here’s how you can do this:

  • Remove the lower radiator pipe and drain the old coolant into a bucket.
  • Next, remove the top radiator hose and flush the system with a regular hose. Continue this until the water has completely drained from the engine’s bottom.
  • Replace the coolant with a new batch, then reconnect the radiator hoses.

The specific procedure might differ based on the car and model you have, so consult the car manual before draining out engine coolant. Having said that, the technique itself can be fairly complex, so unless you are confident and have some experience working with a car engine, you should leave it to a car professional.

Tips for Safe Engine Coolant Disposal

Engine coolant contains poisonous qualities that can harm humans, animals, and the environment, so it must be disposed of carefully after draining. Do not flush it down the toilet or throw it away on the lawn. Transfer the engine coolant to a large plastic container and carry it to your local hazardous waste or recycling site. Often, car parts stores are delighted to recycle the old engine coolant.


If you suspect an engine coolant leak, take action as soon as possible to prevent engine damage. Pay attention to warning indicators such as low coolant, overheating, and white exhaust smoke. If you can’t find the leak on your own, hire a skilled mechanic who has worked on vehicles similar to yours.


1. Can I fix a coolant leak by myself?

If you have worked with cars before, you can give it a try. But make sure to read the car’s manual or watch YouTube video tutorials to see how it’s done. 

While this will save you some money if you do anything wrong during the process and it damages the engine, you will have to splurge big bucks on repairs. If you don’t want the risk involved, it’s best to take your car to a repair shop for a quick checkup.

2. Is a coolant leak serious?

Coolant keeps the engine from getting too hot. If the coolant is leaking and you don’t pay attention to it, the engine will almost certainly overheat and suffer significant damage. So, a coolant leak is serious and you should not overlook this issue.

3. Can I Drive My Car With a Coolant Leak?

Surely you can drive your car with a coolant leak. However, it is not recommended. Coolants work to prevent your engine from overheating and keep it at a normal temperature. If your car is leaking coolant and you keep n driving, you will soon run out of coolant and the engine will overheat. This poses severe danger to the engine and it might also lead to engine failure. 

4. Is it expensive to fix a coolant leak?

The cost of repairing a coolant leak varies greatly depending on the source of the leak and the severity of the damage. Small leaks, such as hose replacements, may be reasonably inexpensive; but, more severe concerns, such as radiator replacement, can be costly.

5. Can I use water instead of coolant?

You can use water in case of emergency. While water can be used as a temporary solution in an emergency, it is not suggested to use water as a coolant for long periods. Coolant contains chemicals that prevent freezing and provide corrosion prevention, making it necessary for good operation.