Car Overheating And Leaking Coolant

Car Overheating And Leaking Coolant (Solved!)

Does your car keep overheating and leaking coolant? If yes, this guide will help you solve this problem. You should take action immediately to fix the leak and stop the overheating before it ruins your engine. So, why is your car overeating and leaking coolant?

Coolant leak is caused by damaged hoses, a failing water pump, damaged radiator, leaking gaskets, etc. The leak causes coolant loss, which will then cause engine overheating due to low coolant levels. Finding the source of the leak and fixing it helps resolve the overheating condition.

In this guide, we share more helpful info about your car overheating and leaking coolant. You’ll discover why this happens, what you can do to fix it, how much you’re likely to spend on repair costs and loads of other helpful info.

Why is your car overheating and leaking coolant?

The simple explanation for why your car is overheating and leaking coolant is that the leak results in loss of coolant. This translates to low coolant levels in the reservoir—causing your engine to overheat.

Loss of coolant can also result in coolant circulation issues which further cause your engine to overheat.

Why is your car overheating and leaking coolant

That said, there are many potential causes for overheating in your car. Coolant leak is most likely to come from a damaged radiator, faulty water pump, blown head gasket, damaged radiator hoses, damaged heater core, bad cylinder heads, or damaged engine block.

Let’s briefly discuss the most common causes of coolant leaks below:

Defective radiator cap

The radiator cap creates a tight seal and ensures proper pressure levels are maintained in your engine cooling system.

If the cap gets leaky, however, it affects proper seal in the system causing coolant to spring out as the pressure exerts out of this system.

Defective radiator cap

A hole in the radiator

Your radiator may also develop holes that notice coolant leaks. If you notice the leak happening at the front part of your car engine, that’s probably a damaged radiator.

Blown head gasket

The head gasket is designed to seal the space between the engine block and cylinder head. If it becomes faulty, it may cause the coolant and engine oil to mix.

In the case of a blown head gasket, you may notice the coolant leaking from the bottom of your engine and dripping out onto the ground.

Blown head gasket

Damaged heater core

The heater core acts as a small radiator and is responsible for dispersing heat to the passenger cabin in your vehicle.

This part can also develop, in which case fluid tends to accumulate in its plastic housing situated at the bottom of the heater core.

Cracked or damaged coolant hose

Coolant in your engine usually flows through various hoses under your car’s hood. If any of these lines develop a hole/crack, they’ll also cause the coolant to leak.

Cracked or damaged coolant hose

Lose or damaged hose connections

The hoses in your cooling system must connect firmly to different components.  These connections are either made through hose clamps while other hoses attach to the comments on their own.

If any of the connections become loose or get worn out, it’s also likely to leak coolant.

Bad coolant expansion tank

If you notice puddles or drips of your engine coolant under your car, near the expansion tank location, that’s a pure sign that you have a failing coolant expansion tank.

The expansion tank is tasked with temporarily holding the expanded coolant of your engine.

Bad coolant expansion tank

After your engine stops running and cools down, the coolant then returns to its usual location. Unfortunately, this tank is usually made of plastic and wears over time. If it breaks or cracks, it will definitely leak the coolant.

What should you do if your car is overheating and leaking coolant?

Coolant leaks should be fixed as fast as possible to shield your engine from overheating and further damage.

What should you do if your car is overheating and leaking coolant

This is how you fix your car overheating and leaking coolant:

Step #1. Find the coolant leak

The first step in fixing a coolant leak is finding where it comes from. This is usually not an easy task, but you can still do it with the correct procedure.

Read:  Car Overheating But No Leaks (Possible Causes & Solutions)

Check out this simplified coolant leak diagnosis flowchart easily and quickly.

Why is your car overheating and leaking coolant

With your engine running, check underneath your car hood to see if you can spot any fluid flowing out and try to trace where it’s coming from.

Also, inspect the hose connections and various components for leaks, including the radiator, radiator cap, water pump, head gasket, and reservoir.

Let your car reach its operating temperature and turn on the AC unit to increase pressure in your cooling system. Increased pressure makes detecting a leak even easier.

Step 2. Fix the coolant leak

Once you have found the source of the leak, fixing the issue becomes easier as you just need to repair or replace the defective part.

For instance, if damaged hoses are the cause, replace them with new ones to stop the leak. Faulty water pump, radiator cap, reservoir tank, etc. will also require replacement with new parts.

If the hose connections are loose, simply tighten them and the leak will stop.

Fix the coolant leak

In case the leak is caused by something more serious, e.g. a blown head gasket, you may want to get a good mechanic to replace it for you. Doing it on your own may cause damage to other parts.

TIP: Once you’re done fixing the leaking issue, be sure to take your car for a test drive of 15-20 minutes to see if the leaking and overheating problem has been fixed or not.

Can you drive a car with a coolant leak?

We advise against driving your car with a coolant leak. Coolant leak is serious business and should be fixed as soon as possible as it eventually leads to loss of coolant or low coolant levels.

If your car runs low on coolant, there will be nothing left to take away the excess heat produced by your engine as it runs and keep your engine cool.

Can you drive a car with a coolant leak

The result is your engine bowing to pressure and spiking the temperature gauge.

With the continued operation, the engine will suffer more extensive damage and it may even break down. Needless to mention, this will leave you with expensive repairs that burn a hole in your pocket.

How much does engine coolant leak repair cost?

The amount of money you spend to fix a coolant leak will depend on the problematic part that needs repair or replacement.

If you found the cause of the leak to be minor cracks or leaks, e.g. clamps and hoses replacement or using a sealer to block holes, then you can spend no more than a mere $100.

However, if the coolant leak is caused by a faulty water pump, radiator, head gasket, etc., then the cost will be more—up to around $500.

How do you temporarily fix a coolant leak

If you involve a professional with the parts replacement, the cost will go up from $500 to $1000 due to labor charges.

How long does it take to fix an engine coolant leak?

The amount of time it takes to fix an engine coolant leak depends on the part of the engine that’s problematic.

If fixing the leak involves minor repairs, such as replacing hoses or hose clamps, then this is easy-peasy and will take approx. 1 hour or less.

How long does it take to fix an engine coolant leak

For larger such as those involving coolant reservoir or radiator replacement, the process will take around 3 to 4 hours.

Major repairs such as gasket head replacement are labor intensive and can take up to 3 or 4 days to fix.

How do you temporarily fix a coolant leak?

Sometimes all you need is a temporary and quick fix for the coolant leak to stop. This is especially true when you found yourself in the middle of nowhere and have limited options.

How Do You Temporarily Fix A Coolant Leak

Here are some helpful methods to temporarily repair a coolant fix:

Method #1. Sealer products

Probably the most popular temporary fix for a leaking coolant is the use of sealer products or stop-leak compounds such as the BlueDevil.

However, we don’t always recommend using this product unless you’re in the middle of nowhere and have no other option.

This is because these sealants tend to clog up the tiny passages inside your heater core and radiator, creating further problems with your cooling system.

Read:  Car Overheating After Accident (Causes & Fixes)

Method #2. The eggshell fix

If you found yourself in the middle with nothing but only some fresh eggs within reach, then this fix is for you.

This is an old trick based on the fact that the heated coolant will cook your eggs and the leak pressure will then attempt to force them out, thereby fixing the leak and buying you more time to get to an auto shop.

This is how you do it:

Step 1. Give your car 5-10 minutes to cool down

Step 2. Pop open the hood and unscrew your radiator cap

Step 3. Crack and drop up to two eggs into your radiator reservoir

Step 4. Confirm if the leak has stopped.

If it didn’t, consider throwing in a few more eggs inside the rad until the leak stops.

Method #3. Using black pepper

What if you don’t have eggs but you have black pepper? In this case, you can also use it to stop coolant leaks in the steps outlined below:

Step 1. Give your engine system time to cool down

Step 2. Open the radiator cap and pour black pepper into your radiator

Step 3. Put the cap back on and start your engine to see if the leak has stopped.

If not, throw in more black pepper until the leak stops.

This fix is based on the idea that the pepper flakes will easily get lodged in the radiator hole, clogging it up, and thus stopping the leak.

Check out this post from for more information about the above temporary fixes for coolant leaks.

Watch the video for more insights on temporarily fixing minor radiator leaks

Car overheating and leaking coolant can be a serious problem that requires immediate attention to prevent damage to your engine. At MotorAdvices, we understand the importance of keeping your vehicle running smoothly and safely. Our website features informative articles on car overheating, including how to diagnose and fix the problem when there are no leaks and what to do after an oil change to prevent overheating. Our article on car overheating but no leaks explains the common causes of this issue and provides tips on how to diagnose and fix the problem. Additionally, our article on car overheating after an oil change discusses the possible reasons for overheating after an oil change and offers solutions to help you prevent it. Visit MotorAdvices to learn more about how to keep your car running smoothly and prevent overheating, no matter what the cause.


1. How long can a car go with a coolant leak?

There’s no specified period of time for you to drive your cart with a coolant leak. Not even the most experienced mechanic knows for sure how long your car can go before the engine overheats and abruptly stops.

2. Can you drive a car with a small coolant leak?

You may drive a car with a small coolant leak. But keep in mind that the coolant may eventually run low and cause your engine to overheat which may then cause further damage to your engine components. Instead of risking this kind of damage, just fix the leak as soon as you notice it.

3. Can a coolant leak fix itself?

Definitely not. A Coolant leak won’t stop itself unless you take the necessary steps to fix the source of the leak. Even if the leak seems like it has stopped, you should be worried because it will come back, even worse than it was before.

Final Verdict

Car overheating and coolant leaking isn’t uncommon occurrence. Coolant leak causes low coolant levels which then causes an overheating condition. The most likely culprits behind these coolant leaks include a damaged radiator, defective radiator cap, damaged extension tank, cracked/damaged hose, damaged heater core, or blown head gasket.

We hope that this has provided you with everything you need to know about finding a coolant leak in your car and fixing it. Remember to fix the coolant leak as soon as possible to shield your engine from overheating and undergoing further damage or even breaking down.

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