How to Fix an Overheating Car
Worn-out radiator hoses, coolant leaks, or a faulty thermostat could be the cause of your overheated car—but how do you fix it? Learn more here.
Written by Bonnie Stinson
Reviewed by Melanie Reiff
You may be able to fix an overheating car by simply adding more coolant. However, a faulty radiator, thermostat, or leak may also be causing the rise in temperature—and these issues cannot be fixed as easily.
One minute you’re driving home from work, and the next minute there is smoke or steam billowing out from under your hood. Perhaps the warning light on your dashboard has illuminated, reporting unusually high temperatures.
An overheated car can be tricky to fix, but we’ll explain everything you need to know to safely handle this situation. Here is a quick guide on how to fix an overheating car from
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4.7/5 rating on the App Store | Trusted by 5+ million customers and 7 million cars4.7/5 app rating | Trusted by 5M+ driversWhy your car overheats
When your car’s cooling system fails, the engine overheats past its normal range of 195°F to 220°F.
In a functional cooling system, the
water pump
pushes coolant through the engine block. The system is regulated by radiator fans and a thermostat. Temperature data is then sent to the engine control unit (ECU) via a temperature sensor.A broken water pump, a damaged head gasket, or a defective cooling fan could stop the cooling system from functioning. If the head gasket is faulty, oil may be leaking into the cooling system. In this case, you might see milky-white oil or white smoke in your rearview mirror.
In most cases, a faulty radiator or a bad thermostat are the two most common causes of overheating.
Bad radiator
A faulty component in the
radiator
may be causing your car to overheat. A leaky hose, a clogged or blocked passage, or a crack could prevent the coolant from cooling the engine.You should never examine a radiator while it’s still hot. Once the vehicle has cooled down, you can carefully check every component that may contribute to overheating.
A slightly worn-out radiator hose could be leaking
antifreeze
, for instance. A cracked radiator cap may be to blame as well, as it cannot properly pressurize and contain the coolant. Damage to the cap may occur as the result of a minor collision—and you may not be able to spot the damage with the naked eye.If this is the case, the good news is that it’s far cheaper to replace a damaged radiator hose than a damaged engine.
Bad thermostat
A malfunctioning thermostat could stop coolant from traveling to the radiator. If the thermostat is not accurately sensitive to heat, then the engine will overheat due to a lack of coolant flow.
A mechanic must drain out the coolant and remove the water neck where the radiator hose is. Then, the mechanic will remove the thermostat and test it in a container of boiling water. (A functional thermostat will close as it cools and open when removed from hot water.)
Again, if a bad thermostat is the cause of your engine overheating, it’s not the worst-case scenario—it’s much cheaper to replace the thermostat than to replace the whole engine.
What to do about engine overheating
If your Check Engine Light illuminates on your dashboard or you otherwise notice your engine’s overheating, the first thing you should do is move to a safe place on the side of the road.
What to do if your engine is overheating
Turn off your air conditioning to reduce the stress on the engine. After turning off the air conditioner, turn up the heat to its maximum setting, which will draw heat away from the engine.
With the engine running, continue to monitor your engine temperature gauge. If it drops into a normal range, then your vehicle has cooled down sufficiently.
Once about 30 minutes have passed, open the hoodto allow the heat to escape. Be very careful since the bonnet may be hot and so will the steam beneath.
Next, check for proper coolant flow. Start by searching for a coolant leak, which would prevent the antifreeze from doing its job. Look for a greenish residue on the radiator hose. You may need to go to a mechanic to get a leaking coolant inspection.
Regardless, you can still top up the coolant reservoir in the meantime. Review your owner’s manual if you’re not sure where to find it.
What not to do if your engine is overheating
Do not ignore the warning light on your instrument cluster. Pull over as soon as you can to investigate the problem.
Do not touch the radiator cap while the engine is still hot.
Do not open the hood immediately upon pulling over.
Do not attempt to examine or repair a vehicle if you feel uncertain, if the vehicle is malfunctioning dangerously, or if the vehicle is in an unsafe location.
If you cannot resolve the issue on your own, please call for roadside assistance.
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Is it bad to keep driving when your car overheats?
Yes, it is bad to drive on an overheated engine. While your vehicle is unlikely to explode, prolonged overheating can cause expensive and irreparable damage to your vehicle.
There are some situations that would exacerbate the damage even more. For instance, you should definitely avoid driving in stop-and-go traffic on a hot summer day if your engine is running hot.
When to get professional help for an overheating engine
If adding more coolant does not help with your overheating engine, then it might be time to seek professional help to diagnose the issue.
A repair shop can safely assess engine damage, including a check on your coolant and oil level. Ask for an inspection of your cooling system and find out if the mechanic thinks a
cooling system flush
would be helpful.If a faulty head gasket needs to be replaced to stop the engine from overheating, you should definitely hire a skilled technician to perform the repair. This is a complicated and time-consuming procedure.
Call a tow truck if you cannot comfortably navigate your vehicle from the side of the road to an auto repair garage.
Find hassle-free car insurance
Many drivers feel completely alone when car troubles arise. When your car is overheating on the side of the road, it’s easy to feel overwhelmed.
We’ve got good news: Whether you need to fix an overheating engine or shop for cheaper car insurance, help is available. Say no to stress and say yes to Jerry.
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FAQs
What are some reasons why a car may overheat?
Insufficient coolant level, a coolant leak, a motor oil leak, a faulty thermostat, a leaky head gasket, or a radiator problem may be the cause of your overheated car engine.
Depending on the problem, repairs may cost anywhere between $200 and $2,000.
What can I do to avoid my car overheating?
Do not allow low coolant to cause overheating. Keep your coolant topped up and commit to regularly assessing the quality of your engine’s cooling system.
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