How do you fix a car that keeps overheating?

Overheating is usually fixable by diagnosing the cooling system and replacing worn parts such as the thermostat, water pump, radiator, or fans, along with ensuring proper coolant levels and airflow. If the problem persists after basic checks, professional diagnosis is advised to prevent engine damage.

Why engines overheat: common causes

Engines overheat for a handful of reasons, ranging from simple leaks to failed components. Understanding the typical culprits helps prioritize that first, critical inspection and makes clear when a roadside stop should lead to a tow or professional service.

Key cooling-system components to inspect

The cooling system relies on coolant circulating through the engine and radiator, controlled by a thermostat and powered by a water pump, with heat extracted by a radiator and cooling fans. Problems in any part can push the engine temperature into the red zone.

If you're on the road and the temperature gauge spikes, prioritize safety with these steps.

• Safely pull over and turn off the engine as soon as possible. Use hazards to alert other drivers if needed.


• Do not open the radiator cap or pressurized reservoir while the engine is hot, as pressurized coolant can cause severe burns.


• Let the engine cool for at least 15–30 minutes before checking coolant levels or opening any caps.


• Check for visible signs of a coolant leak under the car or around the hoses and radiator.


• If you see steam, puddles, or smell sweet antifreeze, arrange roadside assistance and avoid driving farther.

These steps minimize burn risk and prevent worsening the engine damage when overheating occurs on the road.

When you have a safe space to work, start with basic checks to identify simple cooling-system problems.

• Check the coolant level in the overflow reservoir when the engine is cold; top up with the manufacturer-recommended coolant and water mix if needed. Look for cracks or swelling in hoses and signs of leaks.


• Inspect the radiator for clogged fins or debris that blocks airflow; ensure the radiator is not physically damaged.


• Test the thermostat’s operation by noting how quickly the engine reaches operating temperature and whether the radiator gets hot in the expected area. Replace if it sticks closed or opens too late.


• Inspect the water pump for leaks at the weep hole, bearing play, or unusual noises indicating impending failure; replace if suspect.


• Examine the radiator cap for a worn seal or incorrect pressure rating and replace as needed.


• Verify cooling fans engage when the engine reaches operating temperature by using the air conditioning to trigger them or manually testing wiring, fuses, and relays.


• If you have access to a pressure tester, perform a leak/pressure test to uncover hidden leaks or a cracked radiator/heater core.

These checks cover many common, user-serviceable issues and help determine whether professional service is required.

If simple checks don’t resolve the issue, follow this diagnostic repair plan to address the most frequent causes.

1. Confirm the cooling system is sealed and there is no coolant loss; repair leaks first to restore proper pressure.


2. Replace a thermostat that does not open at the correct temperature or remains stuck closed.


3. Replace a failing water pump that shows leaks, grinding noise, or reduced coolant flow.


4. Flush and refill the cooling system with the correct coolant type and mixture; bleed air according to the vehicle’s procedure to remove air pockets.


5. Inspect the radiator for blockages or internal damage and repair or replace as needed to restore adequate cooling capacity.


6. Check and replace a faulty radiator cap if it cannot maintain the specified system pressure.


7. Inspect cooling fans and their electricals (fuses, relays, sensors) and repair or replace components to ensure reliable cooling at idle and low-speed operation.


8. Test for head-gasket issues if overheating persists after all components are replaced; look for coolant/oil contamination, exhaust leaks into coolant, or compression problems.

Some steps require specialized tools and expertise; a professional mechanic can perform pressure tests and component replacements with the proper equipment and safety procedures.

When to seek professional help

If the engine continues to overheat after all basic checks and common repairs, or if you notice steam, white exhaust, milky oil, or persistent coolant loss, stop driving and arrange service. Overheating can cause severe engine damage, including warped heads or a blown head gasket, which require advanced diagnostics and repair.

Summary

Fixing a car that keeps overheating begins with safety and basic checks: verify coolant levels, look for leaks, and confirm that the radiator and fans are functioning. If simple fixes aren’t enough, follow a structured diagnostic path—replace failing components like the thermostat, water pump, radiator, or cap, flush and bleed the system, and test for head-gasket issues if overheating persists. When in doubt, consult a qualified mechanic to prevent costly damage.

Can a car that overheats be fixed?

Yes, an overheating car can often be fixed, but the solution depends on the cause, which can range from a simple fix like adding coolant to a more complex one like replacing a part like the water pump. Common fixes include checking for and repairing leaks, performing a coolant flush, replacing parts like the thermostat or water pump, or clearing blockages from the radiator. If the issue is not immediately apparent or a simple fix doesn't work, it's best to have the car professionally inspected.
 
This video explains what to do when your car is overheating: 57sTeam O'NeilYouTube · Oct 24, 2013
What to do immediately

• Turn on the heater and fan: This will help draw heat away from the engine. 
• Pull over and turn off the engine: Do not continue driving if the temperature gauge remains high. 
• Let the engine cool down completely: before attempting any checks. 

Potential fixes and part replacements

• Check and add coolant: Low coolant is a common cause of overheating. 
• Inspect for leaks: Look for leaks in hoses, the radiator, or the water pump. 
• Perform a cooling system flush: This can remove blockages and old fluid. 
• Replace faulty parts: This may include the thermostat, radiator, water pump, or fan relay. 
• Clear blockages: Clean the front of the radiator if it's blocked by debris like mud or leaves. 
• Replace a bad serpentine belt: A damaged belt can prevent the water pump from working correctly. 

When to seek professional help

• If the overheating continues after basic checks. 
• If you are not comfortable diagnosing or repairing the issue yourself. 
• If the engine was driven for an extended period while overheating, as this could cause serious internal damage that requires professional assessment. 

How do I get my car to stop overheating?

To stop your car from overheating, immediately turn off the air conditioning, turn on the heater to high, and pull over to a safe location as soon as possible. Once stopped and the engine has cooled for at least 30 minutes, check the coolant level and add more if it's low, being careful not to open a hot radiator cap. If the problem persists or you have a leak, have the vehicle towed to a mechanic. 
Immediate actions when your car is overheating

• Turn off the A/C: This reduces the strain on the engine. 
• Turn on the heater: Crank the heat and fan to the highest setting. This draws heat away from the engine and into the cabin. 
• Pull over safely: Find a safe spot to pull over and turn off the engine completely. 
• Pop the hood: This allows hot air to escape the engine compartment. 
• Wait: Let the engine cool down for at least 30 minutes. Never open the radiator cap when the engine is hot as it can cause severe burns. 
• Check coolant: Once cool, check the coolant level in the reservoir. If it's low, add a 50/50 mix of coolant and water, or water in an emergency, to the reservoir. 
• Rev the engine (only if stopped in traffic): If you're stopped and the gauge is rising, put the car in park or neutral and gently rev the engine to about 1500 RPM to get more air and water moving through the radiator. Keep the heat on and avoid using the brake pedal. 

When to call for a tow

• If the temperature gauge continues to rise after adding coolant.
• If you notice a leak in a hose or the radiator.
• If the car overheats again shortly after restarting. 

You can watch this video to learn about the immediate steps to take when your car overheats: 59sAutoZoneYouTube · Jun 28, 2023
Preventative maintenance

• Check coolant levels regularly: Top off the coolant when needed and have the cooling system inspected for leaks during routine maintenance. 
• Inspect the cooling system: Have a mechanic check the radiator, hoses, and thermostat periodically for leaks, clogs, or other damage. 
• Use the correct coolant: Use the right mixture of coolant and distilled water recommended for your vehicle to prevent overheating in summer and freezing in winter. 
• Keep the radiator clear: Ensure there is adequate airflow through the radiator by removing any debris in front of it. 

Can I drive with an overheated engine?

No, you should not drive your car if it's overheating, as this can cause severe and expensive engine damage like a warped head gasket or cracked engine block. The safest and best course of action is to immediately pull over to a safe location, turn off the engine, and allow it to cool down before getting it towed to a mechanic. 
This video explains what to do when your car overheats: 53sTeam O'NeilYouTube · Oct 24, 2013
What to do immediately

• Pull over safely: Find the nearest safe spot to stop your car as quickly as possible. 
• Turn off the engine: This is the most crucial step to prevent further damage. 
• Turn on the heater: To help cool the engine, turn your car's heater on full blast. This pulls heat from the engine and transfers it to the cabin. 
• Wait for it to cool: Do not attempt to open the radiator cap until the engine has cooled completely, which can take at least 15-30 minutes. Opening a hot radiator cap can cause severe burns from pressurized steam. 

What to do after it cools down

• Check coolant levels: After the engine has cooled, you can carefully check the coolant level and add more if it's low. Never pour cold water directly onto a hot engine, as this can cause parts to crack. 
• Call for a tow: Even if you can add coolant, it's still best to have a professional inspect the vehicle to find out why it overheated. Driving with an overheating engine is dangerous, so a tow to a mechanic is the safest option. 

What is the first thing to check when a car overheats?

If the temperature warning light on your dashboard — a small picture of a thermometer — comes on, that could mean your coolant levels are low and could be your first sign of an overheating engine. When it's safe to do so, pull over and check your coolant levels, topping up if necessary.