Why Car Overheated And Died Now Won’t Start [Reasons + Solutions]

The main reasons behind car overheated and died now won’t start are leaking coolant, blown head gasket, cracked cylinder head, a faulty thermostat, malfunctioning cooling fan, melted electronic sensors, dead battery, faulty drive belt, damaged water pump, and loose radiator cap.

Keep reading this troubleshooting guide to learn more about car overheating issues in detail and fix them. You’ll also learn what you should and shouldn’t do when you’re driving a car with an overheating engine and how you can prevent a car from overheating. Let’s begin!

Why Car Overheated And Died Now Won’t Start [Reasons + Solutions]

An overheating car will blow a hose or two and the temperature will continue to rise. So, what happens if your car overheats and you keep driving? The temperature gauge will go into the red section before you realize how quickly it happens and the car will start running rough.

When the car runs rough, that’s usually when you check the temperature gauge and see that it’s on the rise. But it’s already too late by that time as the engine is already running rough. Here are the most common reasons why the car won’t start after it was overheated:

Note: You can also read how to fix 2 Cycle engine hard to start when hot.

1. Leaking Coolant

The car overheated now won’t start is always caused by a coolant leak. The coolant leak can be both the cause or the result of an overheating engine. Worn-out hoses, a damaged radiator, or hose clamps can cause a coolant leak.

The primary job of the head gasket is to seal the internal combustion process and prevent the coolant from leaking. Of course, a blown head gasket will also result in a coolant leak and that means more trouble for you.


Determine the root cause that’s causing the coolant leak and fix it. It could be the hose, hose clamps, radiator, or blown head gasket. Inspect it or take it to a mechanic and have it checked.

2. Blown Head Gasket

If you’re wondering why my car running hot, it could be due to a blown head gasket. It’s the most dangerous consequence of an overheating engine. If this is the issue that’s keeping your car from starting, you’re in a bad spot as it can cost a lot to replace a blown head gasket.

head gasket test

Head gaskets that are made of steel don’t expand as easily as aluminum head gaskets when the engine overheats. So, if your head gasket is made of aluminum, it’ll expand and get blown much quicker than a steel one.


You have to take your car to an expert if you want to replace the blown head gasket in your car. It’s gonna run your wallet dry if you wish to replace it. To make things worse, there can also be other issues along with a blown head gasket that keeps your car from starting.

Before taking apart the engine to replace the head gasket because your car gets hot, you need to do a compression test on it. A blue liquid is put into a tube and if it turns yellow, that means the head gasket is blown. If it stays blue, your head gasket is fine and there’s no need to replace it.

If there are other issues, they’ll quickly add up to the total cost of repairing the car. You should consider if it’s wise to replace the blown head gasket along with more potential repair work or to give up the car.

3. Cracked Cylinder Head

The two most common reasons behind a melted cylinder head are design flows and an overheating engine. In this case, it’s the overheating engine that’s causing the cylinder head to be warped.

The common symptoms of a cracked cylinder head are low level of coolant, leaking coolant, rough engine, engine misfiring, engine overheating, and the mixing of coolant and oil.

The symptoms of a cracked cylinder are similar to that of a blown head gasket. So. it’s worthwhile to have your car looked at by a mechanic to avoid misdiagnosing the root cause of the problem.


Cylinder heads used to be repaired in the past. But modern cars mostly have cylinder heads that are made of aluminum. So, replacing the cylinder head is a more convenient and better option for most mechanics these days.

4. Faulty Thermostat

The thermostat stays open or closed to control the flow of coolant. The thermostat opens when the engine gets hot in normal operation. But when it fails, it remains closed even when the engine gets hot.

faulty thermostat

That results in an overheating engine and a faulty thermostat could be the reason why your engine won’t start. Other common symptoms of a faulty thermostat are frequent temperature fluctuations and false readings.


Replace the faulty thermostat with a functional one. They are not too expensive as it only costs between $30 to $50. But in some cars, it is badly placed that you won’t be able to do it yourself and you’ll have to hire a mechanic to do it for you.

5. Malfunctioning Cooling Fan

If your car is overheating but has coolant, it could be due to a bad cooling or radiator fan. The cooling fan can malfunction when there’s a blown fuse or the fan itself has gone bad when the car overheated. Check for broken wires or damaged relays when you inspect your radiator fan.

Luckily, it’s very easy to check if your radiator fan is working or not. Radiator fans are mounted on top of the radiator in most cases. Check your owner’s manual if you can’t find it.

Unplug the connector of the fan and power it directly with the car battery. The motor will spin if it’s in working condition. Otherwise, it won’t.


If the fan is not working, figure out why it’s not working. If there are broken wires or blown fuses that are causing the problem, you can easily get them fixed. Otherwise, the radiator fan must be replaced.

6. Melted Electronic Sensors

There are many electronic sensors in the car that talks to the ECU in order to function the car properly. When the engine overheats, these sensors can get melted or warped and prevent the car from starting.

If you’re wondering why your car overheated and died now won’t crank, damaged electronic sensors could be the answer you’re looking for.


You’d have to check all the sensors and see if they had been damaged. It’s a good idea to take it to a mechanic to locate all the faulty sensors. Replace all the malfunctioning sensors and your car will be good to go.

7. Dead Battery

The car won’t start if the battery is corroded or damaged due to the engine overheating. You should also check the battery terminals and cables to make sure the battery is in working condition. The corrosion in the battery can also spread and prevent the car from starting.


If you find your car overheated now battery dead, you can fix it by replacing the battery. Pay careful attention that you don’t get a battery of reverse polarity and use the correct one. Make sure the terminals are in good condition to rule out the battery problem.

8. Faulty Drive Belt

The drive belt can become damaged when the engine overheats. It can prevent your car from starting. The most common type of drive belt is the serpentine belt which is found in most vehicles that were made after 1990.

The function of the drive belt is to generate power to the water pump, AC compressor, alternators, and steering pump in your car. Some other symptoms of a faulty drive belt are noise coming from the front of the car, AC stops working, and visible cracks on the belt.


If you suspect that a faulty drive belt could be causing the issue, then having it replaced is the perfect solution. In general, it’s good to replace your drive belt every 100,000 miles or so to keep your engine healthy in the long run.

9. Damaged Water Pump

The water pump is an integral part of the coolant system of your car. It circulates the coolant from the radiator to all parts of the engine. It takes the heat away from the other parts of the engine and keeps the car cool.

But when the water pump fails to do its job, the car overheats. Coolant leaks are also another symptom of a failing water pump.


The water pump has to be replaced if it has gone bad. Fortunately, it’s not too expensive to replace the water pump. In general, water pumps have a lifespan of 60,000 to 100,000 miles. It’s good to change it before it goes bad to prevent any major engine damage like a blown gasket or warped cylinder head.

10. Loose Radiator Cap

Most people often overlook the possibility of a loose radiator cap when they’re diagnosing an engine overheating problem. The radiator cap seals the radiator, prevents the coolant from leaking, and maintains the correct pressure in normal operating mode.

loose radiator cap

But when it goes bad, it lets air into the cooling system and compromises the cooling system as that air goes into the radiator hose and the heater core. It leads to leaking coolant, engine overheating, and engine damage.


If the radiator cap is damaged, you need to replace it. It’s a cheap part to buy and replacement is often free as it only takes a few seconds.

What Should You Do When Your Car Overheats?

If you’re ever caught up in the middle road and see that your car is overheating, you need to act quickly to prevent any major engine damage. Here’s what you should do when your car overheats:

Turn Off AC

The pressure on the engine will be reduced when you turn off the AC. In the meantime, slow your car down as you should be looking for a safe place to pull over to avoid accidents.

Pull Over

Once you find an ideal spot to pull over, turn off the engine and stop the car. Let the car cool down and then check if the temperature gauge goes back to normal. When it does, it’s time to check your car.

Check Coolant Level

The most common cause of an overheating engine is a low level of coolant. It can be either due to carelessness from the owner’s end or a malfunction in the cooling system.

If you have a low level of coolant, you can add coolant to solve the problem. But if you have a coolant leak or you see that coolant has spilled all over your engine, there could be major problems that you need to address to fix your car.

Start The Car Again

How to start car after overheating? You can get the car towed at this point if you suspect there’s a major problem that’s causing your car to overheat. Otherwise, you can start the car again and start driving it again.

Drive with the AC turned off, and windows open to lower the temperature of the car. Keep a close eye on the check temperature gauge and be careful to be in close distance to pull over your car again if it overheats again.

What Should You Not Do When Your Car Overheats?

It can be worrying to see the temperature gauge rise quickly and your engine overheating. But you can take control of the situation by not panicking and keeping a calm mind when you face this problem. Here’s what you shouldn’t do if your car overheats:

Won’t Keep Driving

You shouldn’t keep driving with an overheating engine for two main reasons:

  • You could lose control of the car and cause an accident.
  • You can cause major damage to your engine by driving in this condition.

Blown head gaskets and warped cylinder heads are the major consequences of driving with an overheating engine. It can cost a lot to replace these components. Park in a safe spot to avoid these damages to your engine.

Not Letting The Engine Cool Down

Your curiosity or adrenaline rush can get the best of you and it can cause you to pop the hood as soon as you stop the car. But without letting the engine cool down first, you’re making yourself susceptible to injuries as a lot can go wrong when you open the hood.

Not Addressing The Main Issue

If the car randomly overheats, a lot of people just refill the coolant and keep driving as if nothing has happened. While that works as a temporary fix, you shouldn’t keep doing it if the problem seems to reappear.

If it keeps happening, that means that there’s an underlying issue with the engine that needs to be fixed. Not correcting it at the right time can lead to bigger problems in the long run. So, it’s a good idea to take your car to a mechanic and take care of the underlying problem.

How To Prevent The Engine From Overheating?

Can overheated car not start? If the engine gets overheated frequently and leads to a big problem, the car won’t start on many occasions. But luckily, you can prevent your car’s engine from overheating by taking care of a few key things. Here they are:

Keep Your Car In A Cool Place

Your car will become hot if it is kept in a place where it is hit by direct sunlight. The temperature of the car can be reduced by parking it in a place that has shade. That will bring down the overall temperature of the car.

Whenever you park your car, try to do it in a place that is shaded. You can also use tinted windows to cool down the car if there is no shaded spot.

Keep The AC Off

The motor of your engine works overtime to keep the AC running. It’s not a good idea to treat your car like a sealed spot and keep it closed all the time. Opt for fresh air instead of AC by opening the windows and it’ll keep the engine of the car cool.

Maintain The Level Of Coolant

It’s important to do routine inspections of the coolant and make sure that you’re never close to running out of coolant. You can always check the indicator line on the reservoir to ensure that you have enough coolant.

It’s a good idea to always put the coolant in before you start driving. Because you shouldn’t add coolant when the engine is hot. Also, use a coolant flush as it helps keep the radiator clean.

Check Temperature Gauge

The temperature gauge in your car is the first thing that’ll warn you when you have an overheating engine. If you check it at fixed intervals when driving, you’ll recognize when the car becomes overheated and you’ll be able to stop it.


What are the symptoms of engine damage from overheating?

The first thing you’ll notice is the temperature gauge going through the roof. It’ll also be accompanied by a bad smell, smoke, and coolant leak in most cases.

How long does it take for a car to cool down after overheating?

You should wait for at least thirty minutes to start your car if it stopped because of overheating.

Can a bad radiator cause a car not to start?

Yes, a bad radiator can cause a car to not start. That’s because a bad radiator can lead to an overheating engine and it can prevent your car from starting.

Why would a car start then die?

It’s common for a car to start and then die if the level of fuel is too low. It happens when there’s enough to start the car but not enough to keep it running.


Now you know the most common reasons why your car overheated and died now won’t start and how you can fix them. It can take time to diagnose these issues and have them solved to drive your car again.

We hope this guide has helped you take a step in the right direction to find out the real cause why your car is overheating before spending a ton of money. Drop a comment below if you have any questions about overheating engines.

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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