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​Car Is Overheating When Idling

You could be in serious trouble if your car is overheating when idling. The first thing to do is check the coolant level and ensure enough of it is in the reservoir.

If there isn't, fill up with distilled or coolant from a trusted source like Walmart or AutoZone, and then head over to an auto shop for diagnosis.

If you've already checked the coolant level and are still having issues with overheating, here are six other possible reasons why your car may be idling hot:

1. Low Coolant Level

If the coolant level is low, your car will overheat. Check the owner’s manual to see where the reservoir is and add more if needed.

If you can’t find it there, check behind your kick plate or under the hood on top of one of the hoses running from your radiator into your engine.

If you leak, fix it before it gets worse.

2. Cooling Fan Failure

How cooling fans work: A motor turns the fan when the engine runs. The fan is mounted to a metal shroud that directs air over the radiator and across coolant tubes to cool down the engine.

On older vehicles whose cooling fans are not electrically operated, they spin when you turn on your vehicle's ignition; newer models may use an electric servo motor to power them.

When a cooling fan fails: If your car overheats while idling and then shuts off, it's likely because one or more of your cooling system components have failed (such as a bad water pump) and needs replacing before you can drive again safely; otherwise, chances are high that this could happen again soon—or even worse—that it will lead to a fire.

So if this happens at all during the operation of your vehicle—even once—you should get yourself checked out by an expert ASAP.

3. Radiator Problems

First, check the radiator itself. -This is where the mechanic will look for leaks and cracks, corrosion, damage, or wear and tear.

If there are signs of damage or corrosion on the radiator, it may be time to replace it.

4. Faulty Thermostat

If you’re having issues with your car overheating, a faulty thermostat is one of the most common reasons. Located in the engine block, this component has two main jobs:

To regulate coolant flow between the engine and radiator

To ensure that temperatures within your vehicle stay within an optimal range (between 160 and 180 degrees Fahrenheit)

5. Water Pump Failure

Water pump failure. A water pump is a small but essential part of the cooling system.

The water pump circulates coolant through your car and carries it through the engine block to keep it cool.

If you are experiencing overheating when idling, you may need to have your water pump replaced or repaired.

A faulty thermostat could also cause overheating when idling because, without enough fluid in the radiator, there won't be proper cooling for your engine's operation. In this case, check out our previous article on how to replace a thermostat on your vehicle:

Finally, if there's any leakage in your cooling system—whether from hoses or seals—it will cause an increase in pressure within the system due to expansion;

-this can lead to overheating while driving and idling as well as other problems like corrosion on metal surfaces inside engines which can lead them losing their efficiency over time."

6. Leaks in the Cooling System

If the engine is overheating, you may suffer from a cooling system leak. The most common problem is an internal leak in the radiator.

If this happens, check for fluid on or around your car's engine block and look for wet spots on any connecting hoses.

You can also listen closely while running your car—if you hear hissing or bubbling sounds from somewhere under there, chances are good that it's a leaky radiator.

Another possibility is that water isn't circulating through your cooling system as it should be

—this can happen if there's been damage to your water pump or thermostat (the device that regulates engine temperature).

Ask a mechanic

If you want to see what a mechanic would recommend, you can ask a mechanic here on Video Chat a Pro.

You might even be able to find a mechanic locally who can help out with your car overheating problems.

Most Common Reasons Why Your Car Is Overheating When Idling

Most common reasons for overheating your car when idling:

Your cooling system is low on coolant. Check the reservoir and add more coolant if needed.

If possible, the best time to do this is when you're parked in a safe location where it won't be challenging to find a place to park again later.

You can also check by removing the radiator cap (it's on top of your engine) and checking that there are no leaks or cracks in any part of your cooling system.

You may have a faulty radiator fan or one that isn't working correctly yet still spinning fast enough to keep up with demand while idling but not moving at speed through airflow.

-This could mean needing replacement parts such as a new water pump or thermostat.

Still, it's best to get an expert opinion before proceeding with repairs like these because they can be expensive if done incorrectly or too quickly without taking proper precautions first.


If your car is overheating when idling, there may be a problem with the thermostat. A faulty thermostat can cause the engine to run too hot or have a low coolant level.

If your car is overheating while sitting at a stoplight or in traffic, it could be due to other problems, such as poor airflow through the radiator and heater core or clogged fins.

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