How Long Can a Car Overheat Before Damage?

Maintaining your car’s cooling system ensures that its engine works optimally. Aside from regularly checking if the engine has enough coolant and water, you need to check the temperature gauge as well. If your car goes far beyond its normal operating temperature, you need to know how much time you have left before it gets damaged.

Damage to your car can occur within 30 to 60 seconds after its engine overheats. If the needle on your temperature gauge starts rising, let your engine cool down immediately. Otherwise, the increased temperature can ruin internal components, and in severe cases, it can even deform the engine block.

Read on to know more about what happens when your engine overheats. Find out why overheating occurs and what to do in case it happens.

How Overheating Damages Your Engine

An automobile’s internal combustion engine naturally produces heat since it burns fuel to move the car. Your car’s cooling system helps to keep this heat under control.

If any of the car’s cooling system components fail, the engine temperature will begin to rise. Many factors affect how quickly this temperature goes up, but it may only take seconds for the engine temperature to reach a point where it can cause severe damage to your vehicle.

Below are the most common issues that’ll likely occur if your engine overheats.

Failed Radiator Hose

Radiator hoses are usually made of a reinforced synthetic rubber called ethylene propylene (EPDM). The radiator consists of:

  • An inlet hose. This takes in hot water and coolant, which carries heat from the engine to the radiator.
  • An outlet hose. This takes the water back to the engine after it passes through the radiator’s metal fins to cool down again.

When the engine overheats, the temperature of the coolant or water in the hoses can boil. If it boils long enough, the liquid turns into vapor and expands to a point where it causes the radiator hose to blow off its clamp.

Heat is released when a radiator hose blows, which will briefly lower the temperature. However, less water will circulate, causing the engine to heat up more rapidly.

Blown Head Gasket

The head gasket’s main role is to maintain engine compression by forming a seal around the combustion chamber. It sits between the cylinder head and engine block and keeps oil, coolant, and air from leaking. Head gaskets are typically made of layers of steel interweaved with an elastomer.

When your car engine overheats, the added stress and expansion caused by the increased temperature can damage the head gasket and compromise its ability to seal.

A blown head gasket will result in your engine losing compression, causing the engine to knock, run roughly, or stall. If coolant makes its way to the cylinder chamber, it will affect the air and fuel ratio and cause the engine to misfire.

Warped Cylinders and Pistons

Overheating can damage the cylinders and pistons in your engine. Like any metal, the pistons and cylinders can undergo thermal expansion when exposed to temperatures beyond what they’re designed to withstand.

Thermal expansion can deform the pistons and cylinders, forming a gap between the cylinder wall and piston rings or causing the pistons to scrape the cylinder walls when they move. Once an opening forms, oil can leak into the combustion chamber and cause it to burn during combustion.

Damaged pistons and cylinders will lead to:

  • Poor acceleration
  • Rough idling
  • Excessive oil consumption
  • Thick gray or bluish-white exhaust smoke

Left unaddressed, warped pistons and cylinders can ultimately lead to total engine failure.

Cracked Engine Block

In severe cases, extreme overheating can crack your vehicle’s engine block. The engine block is what houses the cylinders and other significant components of the bottom half of an internal combustion engine.

Engine blocks are usually made of cast iron or aluminum alloy, making them susceptible to thermal expansion when exposed to excessive heat. Aluminum blocks are lighter and provide better heat transfer but are more prone to heat expansion.

A cracked engine block will result in lost engine compression and coolant mixing with oil, preventing the cooling system from maintaining the engine’s ideal operating temperature.

Other symptoms of a cracked engine block include:

  • Poor engine performance
  • Rough idling
  • Misfiring
  • Excessive oil and coolant consumption
  • Visible engine and exhaust smoke

A cracked engine block can be repaired, but professionals will likely recommend replacing it or swapping the engine entirely.

Signs Your Engine Is Overheating

Overheating can cause enough damage to render your engine useless. Detecting an overheating engine early on can mean the difference between a quick trip to the gas station or irreparable engine damage.

Below are different ways to tell whether your engine is overheating.

Temperature Gauge or Indicator

A sure-fire way to tell your car is overheating is by looking at the temperature gauge. In most cars, the normal operating temperature is when the needle is at the center or a little below it. A normal temperature reading will vary across different vehicles, so it’s best to consult your owner’s manual.

In any case, you’ll know a car is overheating if the needle rises past the halfway mark and starts making its way to the “H” or red area of the gauge.

Newer cars may not have a temperature gauge, but they’ll have a warning indicator flash on your instrument cluster if the engine starts getting hotter than it should be.

Visible Steam

As a driver, your primary focus is the road ahead, so understandably, you won’t always have your eyes on the instrument cluster and may not notice the temperature gauge shoot up. However, if you’re looking straight ahead, you shouldn’t miss steam coming from under the hood. 

The steam may look like smoke, but it’s actually the vapor coming from the excessively hot coolant. If the car is in motion, the moisture should make it up to your windshield.

Unusual Odor

Another indication of your engine overheating is an unusual odor. Leaking coolant will have a sweet smell, while the heat will give off a hot scent like boiling water. You can confirm your engine is overheating by looking at the instrument cluster. However, any odd smell should be enough reason to safely pull over and check where the smell comes from.

Poor Engine Performance

When an engine overheats, it will struggle to perform normally.  So, you may notice sluggish acceleration or difficulty in maintaining speed. Although poor engine performance may stem from numerous issues, you can check your temperature gauge or look out for steam or any unusual smells to confirm if your engine is running too hot.

How To Deal With an Overheating Engine

As I mentioned, what you do and how quickly you address an overheating engine can make the difference between a problem that can be resolved and an issue you’ll have to deal with permanently.

Here are the steps you should take if your car overheats.

1. Turn the Heater On

The quickest way to dissipate heat from an overheating engine is to turn your car’s heater on. It may seem counterintuitive, but the heater will draw heat from the engine into the cabin and should significantly reduce the engine temperature.

Turning the heater on allows you to address the overheating issue immediately because it will take you less time than looking for a safe place to pull over and switch the engine off.

2. Pull Over and Turn the Engine Off

After turning the heater on, look for a safe place to pull over. In case you have to drive a little farther or get caught in traffic, mildly revving the engine may help lower the temperature. Also, if your fan and water pump are working, revving the engine will make them work faster to provide better cooling.

Once you find a safe place to pull over, park the car and switch the engine off, but keep the ignition on so the fan continues to spin. At this point, you should turn off your heater to prevent the battery from draining.

3. Wait Patiently

Your engine’s temperature should naturally go down once it turns off. It may take a while for the needle on the temperature gauge to go down, but allow 15 to 30 minutes before taking further action. If the hood is no longer hot to the touch and there isn’t steam from under it, you can open the hood to provide extra ventilation.

Don’t pour cold water over a hot engine or the radiator to speed up the cooling process. The sudden shift in temperature could cause the engine block to crack.

Never attempt to remove the radiator cap while the engine is hot since the pressure can cause scorching water to rapidly rise and burn you.

Check Coolant Level and Refill

Once it’s safe to do so, check the coolant level and refill if necessary. As a precaution, you should cover the radiator cap with a piece of cloth since it may still be hot. Twist the cap slowly to release the pressure gradually before fully opening it.

Add a 50/50 mix of coolant and water until it’s complete. If you don’t have coolant on hand, adding water temporarily may be enough to get you to the nearest service station.

Drive to the Nearest Service Station

After adding water and coolant, switch your engine back on and make your way to the nearest service station. You may have addressed the overheating, and your engine’s temperature may be back to normal, but you still need to determine why the temperature shot up in the first place.

Keep an eye on your temperature gauge as you drive to the nearest service center. If the temperature continues to rise, it would be best to have your car towed to avoid further damage to your engine.

Common Reasons a Car Overheats

There are several reasons that could cause your car to run hotter than usual. Below are common problems that cause overheating.

Low Coolant Level

Even if your engine is tip-top, it can still experience coolant loss through evaporation.  A perfect engine can lose about an inch of coolant yearly. If your car is losing coolant at a more rapid rate, there could be a leak. Check your garage floor for any puddles. The leak could be from one of the hoses or the coolant reservoir.

Coolant contains ethylene glycol, which absorbs heat and keeps your engine from freezing when it gets too cold. If your engine lacks coolant, it will compromise the cooling system’s ability to maintain a desirable temperature.

Clogged Hoses

The cooling system in a car works by maintaining a cycle where the coolant is passed through the engine block to absorb heat. After absorbing heat, the engine goes through the radiator, which is cooled again before returning to the engine.

The coolant travels to the engine and radiator through hoses. If the hoses get clogged by dirt and debris, it will affect the circulation of the coolant and may cause the car to overheat.

Damaged Radiator

The radiator plays a massive role in keeping a car’s engine cool. It’s strategically located where it can absorb vast amounts of air and is often accompanied by a cooling fan. Radiators have many small pipes and fins that serve as a path for coolant and water, which takes the heat away from the engine.

A dirty or damaged radiator can prevent efficient circulation, leading to overheating.

The radiator cap also plays a crucial role in maintaining maximum pressure. Adding pressure increases the boiling point of water, so a defective cap will also cause your car to overheat.

Faulty Cooling Fan

The cooling fan pushes more air towards the radiator to maintain the engine’s ideal operating temperature. If a cooling fan stops spinning, the radiator won’t have the air needed to lower the coolant’s temperature before sending it back to the engine.

Broken Water Pump

A broken water pump is another common cause of overheating. The water pump is responsible for circulating coolant to the engine and back to the radiator. That means if the water pump fails, the coolant won’t be able to carry heat away from the engine block.

Malfunctioning Thermostat

The thermostat regulates engine temperature by keeping coolant from going through the radiator when it’s too cold and letting it pass when it’s too hot. A defective radiator can remain shut, preventing the coolant from reaching the radiator, even when its temperature is hot enough.

Final Thoughts

Always be on the lookout for any signs of overheating because the longer it takes you to address it, the more expensive your repair bill will be.

If your car overheats, give it a chance to cool down before bringing it to a service center. Fixing the root of the problem will always cost less than damaging your engine by continuously using it beyond its ideal operating temperature.

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