8 Common Reason Why Car Won’t Start When Engine Is Hot

If your car won’t start when engine is hot, it’s essential to consider it’s a significant issue in your car. You better remember engine starting issues can ruin your car completely. That’s why you should not ignore any of the issues regarding car engines because it will put you in danger and cost you a high range of money.

You don’t need to be a professional to know why your car is hard to start when hot. An overheated car engine problem is one of the worst issues that can occur in a car. When it comes to the worst car problem, the fixing cost goes up, which can cost you $7000 maximum depending on your car.

To know the reasons why your car won’t start when the engine is hot, you don’t need to be a super-specialist about auto or a professional. By noticing some of the components in your car, you can tell why car won’t start when hot. So, you should finish reading this post carefully and then find out why your car is not starting when engine hot.

Let’s Dive Right In :

What Is Engine Overheating

In order to know why your car won’t start when hot you should know what it means when a car engine overheats. Car engine overheating means when a car engine is running too hot. And if you want to know what happens when an engine overheats, when a car engine overheats, the engine’s aluminum material can begin to warp, expand or even crack.

What Are The Reasons Why Car Won’t Start When Engine Is Hot

The faulty fuel system in your car is the most common reason why your car won’t start when the engine is hot. There are still many reasons why car won’t start when hot, such as the coolant level in your car, car battery, etc. If these issues are not detected in your car, your car has a deeper problem with your engine.

car won’t start when engine is hot
Why car won’t start when engine is hot

Here is some very potential reason why your car won’t start when hot :

  1. Faulty Fuel system
  2. An issue with car battery Terminal or cable
  3. Engine ground connection problem
  4. Something wrong with oil
  5. Clogged air filter
  6. lack of Coolant
  7. Starter motor and circuit issue
  8. Vapor lock in fuel-injected engines

You must know that there can be many reasons why cars get hot, whether it’s for outside weather or internal car issues. Keeping the car engine clean and proper maintenance is the key to avoid car overheating issues. These potential reasons are applicable for any types of causes why your car won’t start when hot.

1. Faulty Fuel System

fuel pump problem car won't start
Car Fuel System

I have seen in most cases that cars won’t start when the engine is hot for faulty fuel systems cars. When your car engine is going too hot, the engine provides a hit, and the certain vapor can be the main obstacle while it is working, which can make it so hard to circulate the fuel.

If the fuel cannot circulate well, the car engine cannot work effectively, and eventually makes your car won’t start when hot. If anything goes wrong with the fuel system or fuel, your car will be disabled anytime and anywhere.

A fuel pressure regulator or fuel injector can also be the reason why your car is hard to start when the engine is hot. Not only this also for the fuel pressure damper in your Car can cause car starting issues. In the fuel system, there is a fuel line. If the fuel lines are too hot for the car engine or weather conditions, the fuel will get the room to evaporate into the fuel line, which makes the engine hard to start.

But nowadays car manufacturers almost solve this issue in cars. Most of the cars have now had a fitted fuel injector. The fuel is kept at high pressure in the fuel injector, so your car will not have to deal with vapor, Which means your car fuel can be circulated efficiently no matter if the engine is hot or cold. Thus, if you’re driving a newer model car and with a fuel injector but your Car still won’t start when the engine is hot, then you should further recharge why your Car still has this issue.

Symptoms of a bad fuel injector :

  • Misfire and down power.
  • Black smoke from the exhaust.
  • Fuel is lacking in cars.
  • Stalling a car.

The bad fuel injector not only makes your car won’t start when hot, but it is also the main culprit for the poor performance of your car.

2. Issue With Car Battery Terminal or Cable

car battery terminal or cable
Car Battery Terminal

Whenever it comes to car starting issues, you should check the car battery properly. Not just your battery health; you have to check the battery terminal or cable. You probably know that the corroded or loose battery terminal or cable is not appropriate for your vehicle to work properly. Your car’s battery terminal issues make your car engine hot no matter what type of engine you have, and that’s why the car won’t start.

You probably know that the corroded or loose battery terminal or cable is not Automobile batteries run on liquid, which means high temperatures can quickly drain car battery life. A little bit of corrosion may not prevent the car from starting, But this little bit of corrosion will spread all over the car battery—corrosion in the car electrical system, which can make your car crank and won’t start.

Corrosion hides in the connectors, and this is hard to remove or clean the corrosion from connectors. So, sometimes you may need to remove the battery terminal from your Car. Checking the corroded or loose battery terminal or cable is crucial, and this is necessary. That’s why if you want to get rid of a car that won’t start when hot problem, you should check the car batteries right away.

4 Symptoms of Bad or Corroded Battery Terminal :

  1. Loss of electrical power
  2. Hard to start the Car
  3. Vehicle not start
  4. Defective Starter motor

The battery terminal or cable is not that expensive like other components in the vehicle, But the battery cable or terminal has a very important role in your Car. It’s necessary to change battery cables if those cables are not right.

A quick way to remove corrosion from the battery terminal :

  • Bring baking soda and warm water.
  • Mix a little amount of baking soda into 8 ounces of warm water.
  • With a soft brush, apply the mix to the battery terminal and posts.
  • With the help of a shop rag to wipe clean the battery terminal and posts.

Removing corrosion is always better for your car battery. Try to check your car battery cable and avoid corroded battery cable in the car.

3. Engine Ground Connection Problem

engine ground connection
Engine Grounding

Like I said before, Corrosion or a loose connection is always bad for every component of your vehicle. Especially corrosion on electrical connectors can make your car hard to start when the engine is hot.

If the engine connection is loose or corroded, the circuit increases resistance effectively, which creates all kinds of electrical issues in your car. Loose or corroded engine ground also affects the several electrical systems and the starting system in your car and makes your car won’t start when engine is hot.

As we know, high temperatures are not suitable for any component or system in our Car. In this case, this is also not applicable. High temperatures affect loose or corroded engine ground connection and make it worse and defective. You cannot diagnose a defective or bad engine ground connection just by looking at the ground. You should know some insight that tells you which one is a bad ground connection or which one is good.

Symptoms of bad engine ground :

  • Hard to start the vehicle.
  • Bad engine ground increases the voltage around the sensor and actuators.
  • Dim lights.
  • Faulty fuel pump.
  • Transmission problem in the Car.

Bad engine ground needs to be fixed in your car because bad engine grounding prevents your battery from being charged properly.

4. Something wrong with Oil

car oil
Car Oil

Wrong oil in the car is unusual, but this might be a reason why your car won’t start. Oil propels vehicles, builds heat, and produces electricity. Motor oil lubricates the moving components of the engine. The oil helps to lubricate the different engine parts to move each other without generating too much friction.

Motor oil lubricates the moving components of the engine. The oil helps to lubricate There are different types of oil. vehicles using conventional motor oil. Conventional motor oil cannot sustain at a high temperature. That’s why oil can break down. The wrong oil in your car cannot run your engine smoothly. That’s why car engines get hot, and cars become too hard to start.

There are different types of oil. All vehicles using conventional motor oil. You always have to be certain which motor oil is right for you. If you don’t know which motor oil your vehicle needs, you should go to a professional mechanic to be sure.

5. Clogged air filter

clogged air filter
Clogged Air Filter

Whether you have a gasoline engine or a diesel engine, an air filter is your car’s most important and useful component. The air filter prevents any dust, particles, sand, and debris from reaching the engine and the air filter ensures a great mixture of air. Air filters have to produce air to the engine and keep it cool. Your car gets hot if the air filter is clogged; that’s why it’s necessary to clean the car air filter.

If you are using an air filter for a long time, dust, particles, and debris can block airflow through the filter. That’s why if you notice your car won’t start when engine is hot, you should check and clean the air filter.

Symptoms of clogged air filter :

  • Decreasing the gas mileage.
  • Car engine making noise.
  • Cars are hard to start.
  • Strong fuel smell.
  • Poor acceleration.

There can be many symptoms in a bad car air filter to know that your car air filter is clogged. So, you need to check for a clogged air filter.

6. Lack of Coolant

coolant
Coolant in Car

The Coolant is a gas or liquid substance. The coolant is used for reducing or regulating the head or temperature of a system in your car. If your car runs out of coolant, your car engine will overheat. And, usually, your car won’t start when hot. That’s why filling up the car coolant level is always recommended.

When you come to an auto repair shop to fix why your car won’t start when engine is hot, you will notice the machine first checking the coolant in your car.

Symptoms of low coolant in car :

  • Rising temperature gauge.
  • Poor fuel economy.
  • Car engine cut-off automatically.
  • Car dashboard warning light.
  • Faulty heating system.

You should not run your car or drive your car with a lack of coolant in your car because a lack of coolant will bring some serious damage to the engine.

7. Starter motor and circuit issue

When you start the motor or press the start button in your car, the battery voltage goes through the starter control circuit and activates the starter solenoid. The starter motor spins and turns over the engine crankshaft allowing the engine to start.

A starting motor allows the current flow to the armature by using brushes and a commutator, and a starter motor keeps the windings spinning inside. Brushes and the springs increase the resistance in the starter motor’s internal electrical circuit. The high temperature of the engine makes this condition more difficult by increasing electrical circuit resistance. And in the end, the car engine won’t start.

Over time the starter motor and circuit connection wear down, and this issue causes why your car won’t start when the engine is hot. Diagnosing the starter motor and circuit issue in the car is not that easy, like others. If you notice these technical problems in your car, I highly recommend you check the car starter motor by a professional.

8. Vapor lock in the fuel-injected engine

vapor lock
Vapor lock

Vapor lock might be a potential reason If you notice that your car is hard to start when the engine is hot. When your car fuel boils in the fuel line and the vaporized fuel creates back pressure in the car fuel system, which prevents the gas from going into the engine. If your car has been idling or turned off and then back on, this can bring you vapor lock issues in your Car.

When your car fuel boils in the fuel line and the vaporized fuel creates back pressure Vapor lock can happen for another reason: clogged vent lines. If your car vent line is blocked, the vapor will mix with fuel to rush out of the tank, which will cause engine performance issues and make your car struggle to start when hot.

Symptoms of vapor lock in cars :

  • Loss of power (Most common sign).
  • No starting.
  • Loss of fuel pressure.
  • Engine Stalling.

Vapor lock issues are mostly related to your car starting. That’s why you should check the vapor lock in your car with an auto mechanic if the car won’t start when engine is hot.

What To Do If Your Car Won’t Start When Engine Is Hot

Checking the car’s coolant level and the battery is the first thing to do if your car won’t start when the engine is hot. When you check these car components, you have to ensure the battery and coolant levels are checked correctly. If you don’t have the proper experience, then you may take auto mechanic help.

After you know what causes the car not starting when engine is hot, now it’s time to know what to do if your car won’t start when hot.

Here are 4 tips when your car is hard to start when engine is hot:

  1. Check Your Car Battery
    You should not forget that the car battery has the maximum head observing dimensions. And when high temperatures always drain the car battery life. If you diagnose your car battery as struggles to start when hot, you first need to start checking the car battery.

    Avoid keeping your car battery at a hot temperature; try to store your car battery in the standard cold temperature. Another thing you must do is proper cleaning and maintenance of your car battery. Believe me; this one good practice will save you a lot of money and have your precious time in the long run.
  2. Look At The Air Filter
    You shouldn’t ignore checking your car’s air filter if your car doesn’t start when hot. Air filters produce air to your car engine and keep it cool and maintained properly. And if your car air filter won’t produce air to the engine gets hot so eventually, make your car not start.

    Air filters can get clogged. That’s why if your car runs hot now won’t start; you have to look at the air filter and keep it working. Don’t hurry; take your time and check the air filter.
  3. Check the coolant level
    Leaking the coolant level in a car is not good practice for car owners because if your car is low on coolant, it can bring more issues than car starting issues. Check the coolant level when your car won’t start when hot. The coolant level should always be full; fill up the coolant level when your car engine is totally cool down.
  4. Replace oil
    You may notice, sometimes car manufacturers recommend different types of oil in the summertime because, in summer, car engines need thicker grade oil than normal. But, before you change the oil, you have to talk to your mechanic and get more knowledge about replacing vehicle oil.

After checking all of these components of your car, and if these components are fine, then your car should start without an issue. After you checked the car battery, air filter, and coolant level, but you didn’t get any issues, informing your mechanic will be the great option to fix your car that won’t start when the engine is hot.

Why Car Won’t Start When Hot Outside

The fuel economy and battery of your car can be the main reason why your car won’t start when hot outside for various reasons why your car won’t start when hot outside or in hot weather. But, most of them are related to car engine performance.

Here is some common reason why your car won’t start when hot outside :

  • Fuel Related Problem
    If your car engine’s extremely hot and high-temperature engine makes a vapor block, which means fuel cannot circulate well as quickly as it should. So, the Car won’t start properly, and car engine performance will be weak.

    Older cars have this issue much more than these days (modern) cars. So, if you are driving a modern car, you don’t need to worry about that much.
  • An issue in Car Battery
    There is no denying that high temperatures drain battery life more than cool or proper temperature. Also, for car battery issues, cars can take a long crank time when warm. So, if your Car won’t start, you should check the car battery.
  • Lack of Coolant
    Sufficient coolant is necessary for the Car. The coolant is used to reduce or regulate the temperature of the vehicle system. For lack of coolant, cars won’t start when the engine is hot and hot outside.

These are the most common reasons why your car won’t start when hot outside. Before you give your car to an auto repair shop you have to check these components properly because if you know what causes your car won’t start when hot outside then maybe you can fix it yourself.

Frequently Asked Questions (FAQ)

Can it be too hot to start a car?

If a car engine gets too hot, then starting a car would be very hard because the car’s fuel cannot circulate properly, and this situation makes it hard for your car to start when too hot. To avoid a car starting an issue, you have to check your car’s coolant level and fill it up.

How much does it cost to fix a car that won't start?

The car won’t start to cost you around $100 to $150 in the USA for diagnosis. But, if you want your car mechanic to fix your car that won’t start, then the cost gets higher depending on what components need to be repaired in your car.

Can a car not start due to heat?

A car cannot start due to heat. The heat of your car always prevents ignition power to the car. Surprisingly, most of the cars won’t start because of overheating. The leak of coolant level in your car and faulty car battery are the main reasons why your car gets heated.

Why would a car suddenly not start?

Your car suddenly does not start for various reasons, but the most common reasons are the broken starter and dead battery. That’s why if your car suddenly shuts off on the road, then take your car step aside from the road and check the car battery and starter.

Can AutoZone check your starter?

AutoZone checks your starter for free, and not only that, but they will also check your car’s battery, alternator, and many more. In every AutoZone in the USA, you can check your car’s components for free.

Final Word

Now, you know why your car won’t start when hot. But, most commonly, your car won’t start when engine is hot because of the faulty battery and lack of coolant in your car. That’s why try to test these two components of your car if your car has overheating issues. Car engine overheating problems should always get the proper and quick attention if you want to maintain the car’s better health.

Whenever you find out why your car won’t start when the engine is hot, you should take action or try to fix that issue right away because if you let that issue stay in your vehicle, this can bring you to a more serious situation. Car owners make mistakes when they let the car engine being heated and think these issues will go away on their own. But, it’s not really the right way to treat car engine overheating issues; you have to find out why car won’t start when engine is hot and fix this issue as soon as possible.

Like I said before, and I always say that proper maintenance of a car is necessary. The fuel system is considered the main culprit for car trouble starting. If your car or truck has a serious issue with anything, you should check that out by a professional.

Now It’s Your Turn

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Which one of the reasons why your car won’t start when the engine is hot?

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