The check engine light is one of the most important warning lights in your car. It alerts you to problems with your vehicle’s engine, transmission, or emissions system. One of the most common reasons for the check engine light to come on is if the engine is overheating.
But can the check engine light come be directly triggered for low coolant? The short answer is yes, it can.
Low coolant levels in your car radiator and coolant system can trigger the check engine light to come on. Low coolant affects the internal engine temperature which is protected by antifreeze, triggering the CEL to come on to alert you of potential engine overheating.
There are several reasons why your coolant level may be low, including a leak in the system, a malfunctioning thermostat, or a blown head gasket. Regardless of the cause, it’s important to address the issue as soon as possible to prevent further damage to your engine.
If you see the check engine light come on, it’s important to have your car checked by a qualified mechanic. They can diagnose the issue and let you know if low coolant is the culprit. It’s always better to be safe than sorry when it comes to your vehicle’s engine, so don’t hesitate to get it checked out.
Can Low Coolant Cause the Check Engine Light to Come On?
Yes, low coolant levels can cause the check engine light to come on. The check engine light is triggered by the car’s computer system, which monitors various sensors in the engine and exhaust system. If the computer detects a problem with one of these sensors, it will turn on the check engine light to alert the driver and it will usually stay on until the issue has been resolved.
The engine coolant, also known as antifreeze, is responsible for regulating the temperature of the engine.
The coolant level in an engine is typically monitored by a sensor in the coolant system. The sensor is usually located in the coolant reservoir, which is a small tank used to fill and check the coolant level. The reservoir is typically made of clear plastic, so the driver can easily see the level of the coolant and the maximum fill line.
The sensor in the coolant system is designed to detect the level of the coolant in the reservoir and send a signal to the ECU if the level drops too low. The ECU then activates the check engine light to alert the driver that there is a problem with the coolant level.
In some vehicles, the coolant level may be monitored by a float switch, which is a mechanical device that is activated when the coolant level drops below a certain threshold. The float switch sends a signal to the ECU, which then activates the check engine light.
Low coolant levels can cause the engine to overheat, which can lead to serious engine damage. When the engine overheats, it can cause metal parts to expand and warp, leading to costly repairs or even engine failure. The check engine light is meant to signal to the driver that there is a problem with the engine or emissions system that needs to be addressed.
One of the sensors that the ECU monitors is the coolant temperature sensor. This sensor measures the temperature of the engine coolant and sends it’s readings back to the ECU when the engine is running.
How Does Low Coolant Affect the Engine Temperature and Lead to Overheating?
Low coolant levels can affect the engine temperature and lead to overheating, which can also trigger the check engine light. Coolant plays an important role in regulating the temperature of the engine. It circulates through the engine and absorbs heat, which is then dissipated through the radiator.
If the coolant level is low, there will not be enough coolant to absorb the heat generated by the engine. This can cause the engine temperature to rise, which can lead to overheating.
Overheating can cause serious damage to the engine, including warped cylinder heads, blown head gaskets, and cracked engine blocks.
What Causes the Check Engine Light to Come On for Low Coolant?
The check engine light can come on for low coolant for a few different reasons. Here are some of the most common causes:
- Coolant leak: The most common cause of low coolant levels is a leak in the coolant system. A leak can occur in the radiator, hoses, water pump, or other components of the coolant system, causing the coolant level to drop and triggering the check engine light.
- Faulty coolant level sensor: The coolant level sensor is responsible for detecting the level of coolant in the system and sending a signal to the engine control unit (ECU). If the sensor is faulty or malfunctioning, it may send an incorrect signal to the ECU, causing the check engine light to come on.
- Faulty thermostat: The thermostat is responsible for regulating the flow of coolant through the engine. If the thermostat is stuck closed, it can cause the engine to overheat and trigger the check engine light.
- Failed water pump: The water pump is responsible for circulating the coolant through the engine. If the water pump fails, the coolant will not circulate properly, causing the engine to overheat and triggering the check engine light.
- Clogged radiator: If the radiator becomes clogged with debris or sediment, it can prevent the coolant from flowing properly through the engine, causing it to overheat and triggering the check engine light.
It’s important to note that the check engine light can come on for a variety of reasons, and low coolant is just one of them. If the check engine light comes on, it’s important to have the vehicle inspected by a qualified mechanic to determine the cause of the issue and ensure that the vehicle is running properly.
What Are The Symptoms of Low Coolant With A Check Engine Light?
Low coolant in a vehicle can cause several symptoms that can be easily identified.
The following table lists some of the most common symptoms of low coolant:
| Symptom | Description |
|---|---|
| Low coolant level | The coolant level in the radiator or overflow tank is below the minimum level. |
| Overheating | The temperature gauge on the dashboard shows that the engine is overheating. |
| Coolant leaks | There are visible signs of coolant leaks under the vehicle or around the engine compartment. |
| Steam coming from the engine | Steam or smoke is coming from the engine, indicating that the coolant is boiling. |
| Sweet smell | There is a sweet smell inside or outside the vehicle, indicating that the coolant is leaking. |
How Low Coolant Symptoms Can Trigger the Check Engine Light
Low coolant can cause the engine to overheat, which can trigger the check engine light. When the engine overheats, it can cause damage to the engine components, such as the head gasket, which can lead to expensive repairs. The check engine light can also be triggered by low coolant level or coolant leaks.
When the engine is low on coolant, it can cause the temperature sensor to malfunction, which can trigger the check engine light. The coolant level sensor can also malfunction, causing the check engine light to come on. Coolant leaks can cause the engine to run hot, which can trigger the check engine light.
In summary, low coolant can cause several symptoms that can be easily identified, such as low coolant level, overheating, and coolant leaks. These symptoms can also trigger the check engine light, indicating that there is a problem with the engine. It is important to address low coolant symptoms promptly to avoid expensive repairs and ensure the safety of the vehicle.
What Next – How to Diagnose And Fix Low Coolant
Diagnosing the cause of a coolant leak can be difficult, especially if it is a small leak or if the coolant is only leaking at certain times such as when the engine is off or the vehicle is parked up for a few days. If you are not experienced at fixing coolant leaks then you should leave it to an expert.
Before getting a mechanic involved, it’s worth checking and topping up the coolant yourself to see if there actually is a leak or if the coolant level has just dropped because it hasn’t been flushed or topped up in a while.
Here are some tips for checking and topping up coolant leaks and an outline of whats involved if you decide to fix a coolant leak yourself. Remember to check a service repair manual for your specific vehicle before starting to see what coolant your vehicle uses and how to top it up.
1. Checking Coolant Level
The first step to diagnosing low coolant is to check the coolant level. This can be done by locating the coolant reservoir, which is usually a translucent plastic tank located near the radiator.
The coolant level should be between the minimum and maximum marks on the reservoir when the engine is cold. If the level is below the minimum mark, then the coolant is low and needs to be topped up.
2. Refilling Coolant
To refill the coolant, first, make sure the engine is cool. Then, locate the radiator cap or coolant reservoir cap and remove it. Next, add a mixture of 50% antifreeze and 50% water until the coolant level is just below the maximum mark on the reservoir.
Replace the cap and run the engine for a few minutes until it warms up to allow the coolant to circulate. Then turn off the engine and wait for 15 minutes before checking the coolant levels again
3. Fixing A Coolant Leak
- Locate the source of the leak: The first step in fixing a coolant leak is to locate where the leak is coming from. Common areas for leaks include the radiator, hoses, water pump, and heater core. Check these areas for signs of a leak, such as wet spots or stains.
- Pressure test the system: If you can’t locate the source of the leak, a pressure test can be performed to pressurize the cooling system and identify the leak. A pressure tester is attached to the radiator or coolant reservoir and pressurizes the system to a certain level. If the pressure drops, it indicates that there is a leak in the system.
- Replace damaged components: Once the source of the leak has been identified, the damaged component will need to be replaced. For example, if a hose is cracked or damaged, it will need to be replaced. Similarly, if the radiator is leaking, it will need to be replaced.
- Flush the system: After the damaged component has been replaced, it’s important to flush the cooling system to remove any debris or sediment that may have accumulated in the system. This can be done by draining the old coolant and refilling the system with fresh coolant.
- Test the system: After the repair has been made and the system has been flushed, it’s important to test the system to ensure that the leak has been fixed and that the system is functioning properly. This can be done by running the engine and checking for leaks, monitoring the temperature gauge, and checking the coolant level.
It’s important to note that fixing a coolant leak can be a complex process, and it’s often best to have your vehicle inspected by a qualified mechanic to properly diagnose and fix any issues with the cooling system.
What Happens if You Ignore the Check Engine Light for Low Coolant?
If you ignore a check engine light for low coolant, it can lead to serious engine damage and costly repairs. Here are some of the potential consequences of continuing to drive with low coolant:
- Engine overheating: Low coolant levels can cause the engine to overheat, which can lead to serious engine damage. When the engine overheats, it can cause metal parts to expand and warp, leading to costly repairs or even engine failure.
- Reduced engine performance: When the engine is low on coolant, it may not be able to perform at its best. This can lead to reduced engine power, decreased fuel efficiency, and other performance issues.
- Increased emissions: Low coolant levels can also lead to increased emissions, which can cause the vehicle to fail an emissions test or run afoul of environmental regulations.
- Expensive repairs: If the engine is damaged due to low coolant levels, it can lead to expensive repairs or even the need for a new engine. This can be a costly and time-consuming process, and may leave you without a vehicle for an extended period of time.
In short, ignoring the check engine light for low coolant can lead to serious consequences for both your vehicle and your wallet.
If the check engine light comes on, it’s important to have your vehicle inspected by a qualified mechanic to properly diagnose and fix any issues with the cooling system before they lead to more serious problems on the road.
How To Help Prevent Low Coolant With A Check Engine Light
To prevent the check engine light from coming on due to low coolant levels, it is important to maintain the coolant system properly. Here are some preventative measures that can be taken:
- Regularly check the coolant level and top it up if necessary. This can be done by looking at the coolant reservoir tank or by checking the dipstick.
- Check the coolant system for leaks. Leaks can cause the coolant level to drop rapidly and trigger the check engine light.
- Replace the coolant at regular intervals as recommended by the manufacturer. Old coolant can become contaminated and lose its effectiveness.
- Make sure the radiator cap is tight and functioning properly. A loose or faulty radiator cap can cause the coolant to evaporate and trigger the check engine light.
In addition to preventative measures, regular maintenance is also important to keep the coolant system in good condition. Here are some maintenance tasks that should be performed:
- Have the coolant system flushed and refilled at regular intervals. This will remove any contaminants and ensure that the coolant is effective.
- Replace the thermostat if it is not functioning properly. A faulty thermostat can cause the engine to overheat or not reach the proper operating temperature.
- Inspect the radiator and hoses for damage or wear. Damaged hoses or a damaged radiator can cause leaks and trigger the check engine light.
