Car Overheated Now Won’t Start (What To Do)
Chris is Head of Content for FindTheBestCarPrice and is based out of Philadelphia, PA. As a seasoned automotive industry analyst and car enthusiast, he ensures the highest level of quality across all our content and curates our picks for the best deals each month.
Chris studied information systems and marketing at Drexel University and writes about a wide range of topics ranging from car buying tips to troubleshooting common mechanical issues.
When he’s not thinking about cars, he likes to stay in with his dog and make an “attempt” to finish a crossword puzzle (he’s not quite at the Saturday/Sunday level…yet). As a former cheesemonger, Chris still has a “sharp” passion for all things cheese, and his fridge is always loaded with it!
Car overheating is a common problem that can cause your vehicle to stop running and leave you stranded.
If this has ever happened to you, you know how frustrating it can be. But don't worry. You're not alone. Many drivers have experienced this issue, and there are solutions to get you back on the road.
Let’s discuss why your car overheated and how to prevent it from happening again. We will also provide tips on how to handle the situation if your car overheats safely and won't start.
So, whether you're a seasoned driver or a new one, read on to learn more about how to deal with a car that overheats and won't start.
Table of Contents
- Why Do Cars Overheat?
- Why Does Car Overheat Now Won’t Start?
- What To Do When a Car Overheats
- Best Car Deals by Category
Why Do Cars Overheat?
Thermal energy arises from various sources, including the movement of two objects, chemical reactions, or friction.
Upon inspecting the engine bay, the underlying issue may be obscure as the fuel combusts within the engine block, pistons reciprocate, and multiple components undergo friction while the engine operates.
If this process continues without preventive measures, the vehicle can only be operated briefly before overheating.
Lubricants such as oil and grease are employed to mitigate heat generation from friction and motion.
This is the primary rationale for adhering to a regular oil-changing regimen, as oil has a low coefficient of friction and provides long-lasting lubrication. This results in less heat generation from friction and motion.
However, what about the combustions occurring in the engine block? Short of switching to a Tesla, it is impossible to avoid this.
Instead, vehicles integrate a secondary system that dissipates the generated heat and regulates the engine's temperature.
If the engine becomes too hot, components will warp, materials will melt, and the fuel will combust unpredictably.
The components will crack and deteriorate at a critical point, leading to engine seizure and rendering the vehicle immobile. This is where the "coolant system" comes into play.
The coolant system draws heat away from the engine and circulates a cold liquid across hot components. This process extracts heat from heat-sensitive parts and maintains an optimal operating temperature.
The coolant system comprises multiple intricate components, such as a coolant-circulating pump, hoses for conveyance, a heat-dissipating radiator, an auxiliary cooling fan, and a temperature-regulating thermostat that modulate the flow of coolant.
Why Does Car Overheat Now Won’t Start?
The following are the leading causes why a car will fail to start after overheating:
1. A Loose Battery
When inspecting under the hood, commencing with the battery is a reasonable first step that can save considerable time if it is the root cause of the issue.
The battery's terminals should be securely fastened to the battery, the casing should be entirely seated, and there should be no signs of bulging or leakage.
An anomalous battery can lead to a substantial amount of additional heat. Due to its proximity to the engine block and the lack of any cooling mechanism for the battery, it promptly dissipates heat throughout the engine bay.
2. A Blown Gasket
Gaskets are widely employed in various locations of your vehicle to maintain the sealing of components, thereby preventing fluid leakage and cross-contamination.
If a gasket is fractured, ruptured, or torn, the seal is compromised, and fluids can escape. In the case of a blown gasket responsible for containing the oil, the resultant oil leakage could trigger overheating in your car.
Identifying a blown gasket necessitates the examination of the rubber material utilized under the hood to ensure no seepage of fluids from the joints.
3. A Cracked or Warped Head
If your engine experiences severe overheating, the cylinder head can sustain significant harm, arguably the costliest error when dealing with an overheating car.
The cylinder head confines the explosions and movements within the engine. If there is any damage to this component, the engine's performance becomes erratic, and it may fail to start up again.
4. The Engine Oil
Oil is the engine's lubricant, ensuring the moving parts remain lubricated and cooled.
Over time, the oil accumulates impurities and loses effectiveness, underscoring the importance of adhering to your vehicle's recommended oil change intervals and avoiding postponements.
Procrastinating oil changes can result in insufficient "fresh" oil to adequately cool down the engine, or it may reveal the presence of an oil leak. The system's lack of sufficient oil will invariably lead to the car overheating.
5. A Compromised Air Filter
Airflow is a significant factor in maintaining an optimal temperature for your car's engine. A filtration system is implemented to shield vulnerable engine components from hazardous airborne debris.
The incoming air is sifted through a filter composed of minuscule apertures, which allow air to flow through but prohibit the passage of stones, dust, and other particulates into the engine.
Nevertheless, these filters gradually accumulate sediment and impurities. If the air filter is obstructed, it limits the flow of air and ultimately hinders the cooling process, causing the engine to overheat.
6. A Faulty Fuel System
If fuel is delivered to your engine excessively, the air-fuel mixture will be imbalanced. An overly rich mixture will produce excess heat without generating enough energy, leading to an engine that operates at a higher temperature than it should.
With a persistent supply of excessive fuel, your engine will rapidly overheat and exacerbate other issues on this list.
Another complication is the potential creation of too much vapor by this mixture. This hinders airflow in the engine, accelerating the overheating process.
This issue can be incited by almost any constituent present within your fuel system, including but not limited to the fuel pressure regulator, a fuel pressure damper, fuel lines, or even the fuel injector.
7. Faulty Car Starter
If your car has experienced overheating, the starter motor could have also been affected by the excessive heat. The starter motor is responsible for initiating the ignition process, which powers your engine, and is an essential component for starting your car.
Rather than using brute force, starting an engine requires significant energy and can be challenging to accomplish.
As such, initiating the engine requires turning a key in the ignition, which activates a petite starter motor, and in sequence, revolves the crankshaft, thereby bringing the engine to life.
However, if the starter motor, wiring, or solenoids become overheated, they can melt or become disconnected. This can result in starter motor failure, rendering you incapable of starting the engine despite turning the key.
Since the starter motor assembly mainly comprises electrical components, it's heat-resistant. Even a minor increase in temperature can cause it to overheat and malfunction.
8. Coolant Level
The coolant level is also another possible cause of car overheating. The system only utilizes the amount of coolant present in the reservoir.
Inadequate coolant levels mean that the engine won't have enough liquid to dissipate heat, causing potential damage to heat-sensitive parts.
The loss of coolant can occur due to a leak or natural depletion over time. It is advisable to start by checking the coolant reservoir in the engine bay's rear section. The reservoir's fluid level can be checked using the indicator.
What To Do When a Car Overheats
It is essential to know the appropriate course of action when you first notice your car overheating, which typically happens while the car is in motion, as idling rarely generates sufficient heat to cause engine overheating.
1. Pull Over and Cease Driving
As the first step, you must pull over and switch off the car engine immediately. Continuing to drive while the engine overheats can result in significant damage to the engine block and head gasket.
The overheating mentioned above can culminate in the engine block and head gasket failure, jeopardizing the entire vehicle and incurring substantial repair expenses.
Halting the vehicle and powering down the engine can effectively thwart further harm. It is not advisable to risk driving to the next mechanic; instead, pull over as soon as you find a safe location.
2. Raise the Hood
Next, raise the hood of the car. This serves a dual purpose - it aids in cooling down the engine and allows more airflow into the bay. Moreover, it enables you to start investigating the cause of the overheating issue.
It is crucial to exercise caution while opening the hood when the car engine is overheating. The engine components may be hot enough to cause burns if touched. Hence, one must avoid contact with any hot engine parts.
3. Inspect the Coolant Level
According to its definition, the fluid is responsible for maintaining your engine at a cool temperature.
Fortunately, checking and refilling the coolant is a quick process that can be done on the side of the road.
The coolant reservoir is typically located in the rear corner of the engine bay and can be identified by its plastic material, whereas the metal cap is located separately.
Adding coolant to the reservoir instead of the inline cap is recommended due to the reservoir's cooler and less pressurized environment.
The inline cap can be dangerous to open as it may result in the cap flying off, releasing hot vapors, and burns to the hand.
Additionally, the coolant reservoir provides a clear indicator of the recommended fluid level. Adding more coolant is necessary if the fluid is below the indicated line.