The furthest you can drive an overheating car is about a ¼ mile before you risk irreversible engine damage. While some vehicles could still make it as far as 20 miles, we would never recommend driving very far with an overheating engine.

Today’s post will answer all your questions concerning an overheating car, from the causes of overheating to how long a car can overheat before engine damage.

So, let’s get to it.

 

What Happens If You Keep Driving A Car That’s Overheating?

Modern internal combustion engines produce lots of heat to keep the car running. The coolant or antifreeze absorbs the heat. When your cooling system is not working correctly, your engine will keep overheating until you get it fixed. 

What’s more, driving an overheating vehicle can cause all sorts of problems.

 

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A Damaged Radiator 

Suppose your vehicle still has coolant in it when it’s overheating. In that case, the antifreeze will boil and expand, causing excess pressure in the radiator hoses. The hoses may end up bursting, and all that coolant will spill over. In addition, you may end up with failed radiator stems.

 

Warped Engine Parts 

Most engine parts can handle high temperatures, but they will start to warp when they exceed this maximum temperature. For example, cylinder heads are made of aluminum which can melt quickly in high temperatures. Warped cylinder heads could lead to a blown head gasket, one of the most expensive car repairs.

 

Signs You Have Warped Cylinder Heads. 

  • Misfiring
  • Decreased engine power
  • Oil leaks 
  • Excessive oil burning

Other than the cylinder heads, the electrical wiring, welds, sensors, seals, pistons, cranks, and camshafts can also warp. Any of these would cause an expensive repair.

 

Blown Head Gasket

After a warped cylinder head, the next thing that you’ll deal with is a blown head gasket. Repairing a blown head gasket is both expensive and labor-intensive. Since its work is to seal the cylinder’s firing pressure when a head gasket blows, the coolant and engine oil will leak into the cylinders.

 

Signs You Have A Blown Head Gasket 

  • White smoking coming from the exhaust 
  • Unexplained antifreeze loss without any leaks 
  • Bubbling in the coolant reservoir and radiator
  • Milky white tint in the oil

 

How Long Can A Car Overheat Before Suffering Damage?

It’s risky to keep driving a car that’s overheating. As we’ve mentioned, your car may go a couple of miles. Still, in most cases, the vehicle will stop running when the temperature reaches its maximum. So, you don’t want to roll the dice and drive it as far as it can get if you can help it. 

When a car overheats, the best course of action is to pull over at a safe location, turn off the engine, and have the vehicle towed to a local garage.

 

What Are Common Causes of Overheating?

 

BookMyGarage branded infographic detailing common causes of overheating in a car

 

There are several problems that can cause a car to overheat. If you’re wondering what could be going on in your vehicle, here are the common causes of overheating.

 

Low Engine Coolant 

Your vehicle’s cooling system relies on antifreeze to keep the engine cool. When the amount of coolant is inadequate, it’s not efficient at absorbing the heat, so it may boil over. To this end, the engine temperature will increase, and it can even lead to the engine seizing or locking.

 

Cooling System Leaks 

Coolant is supposed to remain at the same level in a properly functioning vehicle. However, cracked, damaged, worn out, or loose hoses could be causing coolant leaks. Hence, the coolant will not flow to the intended parts causing the car to overheat.

Puddles under the car that appear orange, green, or blue often indicate leaking coolant. If you see any of these as you go about your car maintenance routine, don’t ignore them. Book an appointment at a local garage to get the problem fixed.

 

Broken Water Pump 

Coolant is a mix of antifreeze and water. A water pump drives the coolant into the various engine components. Therefore, it will not supply the engine with sufficient coolant to keep it running at optimal temperatures when it’s broken or damaged.

 

Malfunctioning Thermostat 

Another common reason for an overheating engine is a bad thermostat. A thermostat regulates the coolant, which keeps the engine from overheating. Thermostat failure causes irregular temperature readings, preventing coolant from flowing as intended. This leads to an unwanted temperature increase.

 

Damaged Radiator 

The radiator decreases coolant temperature enabling it to keep absorbing heat. Hence, when it has issues, it will keep the coolant warm and reduce the coolant’s capability of cooling the engine. 

 

How Do I Know If My Engine Is Damaged from Overheating?

Unfortunately, overheating is not one of those problems that you can ignore and hope that it goes away. It’s a matter of time, but your engine will suffer damage. So, if you suspect engine damage from overheating, these are the things to look for.

 

Ticking Sounds 

Ticking sounds mean that there’s not enough oil to lubricate the parts. This is often due to overheating since the oil loses its lubricating power in high temperatures and instead acts like water. Therefore, the engine parts will scrape against each other, causing the ticking sounds.

 

Engine Detonation 

An engine detonation, also known as engine knock, happens when fuel combusts before reaching its maximum combustion state. Thus, the amount of energy you receive from the gas is minor, and your fuel economy will suffer. If you notice power loss accompanied by low MPG (miles per gallon), your engine is probably damaged from overheating.

 

Scuffed Pistons 

Metal parts expand in high temperatures. Pistons in the engine are the common culprits of expansion. When they expand, they will start to touch the walls of the engine, resulting in scuffing. You will see scratched patches on the wrist pins and the piston ring lands. 

Scuffing leads to piston failure since the edges wear down. In addition, gasoline may also move past the pistons increasing the risk of further damage. That’s why scuffed pistons are one of the most critical signs of a damaged engine.

 

Blown Head Gasket 

Perhaps the surest sign that your engine is damaged from overheating is a blown head gasket. Since it’s expensive to repair a blown head gasket, always ensure that the cooling system is working correctly.

 

Cracked Engine Block 

A cracked engine block is far worse than a blown head gasket or warped cylinder head because it means your vehicle needs a new engine. Fortunately, it’s a rare occurrence that only happens if you ignore all the other signs of overheating. 

Nevertheless, it’s difficult to diagnose a cracked engine block since it presents similar signs to those of a blown head gasket or warped cylinder blocks.

 

How Do You Fix A Car That Overheats?

A car that overheats needs attention as soon as possible. The first thing you’ll want to do is pull over and turn off the AC (if it’s on) and then wait for the engine to cool down (about 30 minutes) before taking any further steps. 

If you can’t pull over, turn on the heater. Although it seems counterintuitive, turning on the heater will pull some of that heat from the engine and direct it into the cabin. At this point, you will need to roll down the windows for the heat to escape. 

After you’ve come to a safe stop and the engine has cooled down, perform a visual inspection to see if your coolant is leaking or if you have a bad fan or radiator. Perhaps you can add coolant and get the vehicle to a mechanic. When this is not possible, have the car towed to a garage. 

The permanent fix for a vehicle that overheats depends on what’s causing it to overheat. Nonetheless, professionals can get to the bottom of the issue and prevent constant engine overheating. 

To find the cause of your issue, enter your vehicle reg and postcode into our online booking tool to book a FREE visual inspection for your radiator repair at a garage near you. You can filter by distance, availability or price and see the unfiltered ratings and reviews of every garage to find the best one for you.

 

 

Frequently Asked Questions (FAQs)

1.   Why is My Car Overheating, But it Has Coolant in it?

When your car has coolant, but it’s still overheating, it’s likely that the coolant is not circulating as it should. In this case, the water pump can be faulty, there’s a blockage in the radiator, or the thermostat is stuck.

 

2.   How to Tell if Your Car is Overheating Without a Gauge?

Without a gauge, you can still tell that your car is overheating. You may see white smoke coming from the tailpipe, hear noises from the engine, notice odd smells, and experience acceleration issues.

 

Final Thoughts 

You can only drive an overheating car about a quarter-mile or 30-60 seconds. If you notice any of the warning signs mentioned above, it’s not advisable to continue your journey. Instead, you should call a recovery truck and get towed to a local garage for a repair. It’s not ideal to continue driving a car that overheats since it can cause irreparable engine damage.

 

You can read more of Donald's articles on his website, DC Car Care.