Signs of a seized engine and what to do about it

Owning a car comes with a lot of responsibility. These high-performance machines need regular maintenance, especially when it comes to the engine. Ever had that awful moment when your car won’t start and all you’re left with is dead silence? A seized engine is one of the worst things a car owner can face. It’s not only costly but can take a lot of time to fix. Catching the signs early, though, can save you from bigger problems down the road. Hopefully, you’ll never experience it, but if you do, knowing the symptoms of a seized engine could make all the difference.

What is a "seized" engine

A seized engine happens when the internal components of your car’s engine get stuck, stopping the crankshaft from rotating as it should. In simple terms, a seized car engine won’t turn over at all or only partially because something inside has failed. It’s often described as a “locked up” engine or “frozen” engine, meaning the engine won’t run. This can happen for several reasons, like not enough lubrication, overheating, or damage to engine parts like pistons, cylinders, or bearings. When an engine seizes, it’s completely unresponsive, leaving you unable to start the car.

Warning signs of a seized engine

It’s pretty rare for an engine to seize without any warning. There are usually signs that something’s wrong, like knocking noises, poor engine performance, the oil light coming on, and other red flags.

If your car's engine isn’t performing well, the check engine light comes on, or you’re hearing strange noises from under the hood, it’s a good idea to get the engine checked out. Are you worried it might be a seized engine? If you notice any of the following signs, you should get it checked out:

The engine doesn’t crank or start

The main sign of a seized engine is when your car won’t crank or start. Sometimes, the engine might try to turn over a little—usually with some strange noises—but it won’t crank or run like it should. You might also hear a click or clunk as the starter tries to engage.

Warning lights on the dashboard stay on

If the Check Engine or Engine Oil light stays on, it’s likely a warning that something's going wrong with your car’s engine.

It's making light tapping or knocking sounds

In the early stages of the problem, you might hear a light tapping or knocking sound while driving. This happens because the starter motor is trying to turn the engine, but it can’t rotate due to the seized parts. The starter may keep engaging, but the engine just won’t start.

It's making thundering knocking sounds

As things get worse, you’ll hear loud, thunderous knocking sounds, almost like metal hitting metal. This is called a "dead knock," and it happens when the piston rod slams into the crankshaft. In some cases, though, you won’t hear anything at all when you try to start the engine. That usually means the engine is completely locked up and not moving at all.

The engine is frequently overheating

A seized engine often overheats because the lack of lubrication creates too much friction between the parts. If your engine is constantly overheating, this excessive heat could be a warning sign.

The engine is producing fumes/smoke or a burning smell

Another sign of a seized engine is smoke coming from under the hood. When the starter can't get the engine running in this state, the wiring can overheat, leading to smoke and sometimes even flames.

You can see loose motor parts

If a part inside the engine, like the piston, becomes loose, it can actually break through the cylinder block. You’d usually spot this issue by checking under the hood.

The most common reason for an engine to seize is a lack of engine oil. With insufficient engine oil, parts rub together, causing friction, overheating, and, eventually, engine failure. Water or rust buildup inside the engine can also lead to this problem. While damaged engine parts can sometimes cause a seizure, it’s pretty rare for that alone to lock up an engine.

The engine oil is contaminated

When checking the engine oil level, the dipstick might show metal shavings or debris in the oil, which is a sign that the internal parts of the engine are grinding against each other.

If you think your engine might be seized or notice any of these symptoms, it's important to act fast. Trying to start the engine or keep driving can make the problem worse and lead to even more expensive repairs. A seized engine usually needs a professional mechanic to figure out what's going on and decide whether it can be fixed or needs an engine replacement.

Causes of a seized engine

A seized or locked-up engine is a serious problem, and it can happen for a number of reasons that stop the engine from turning or working as it should. Here are the main causes of a seized engine:

A lack of lubrication

Engines need oil to keep the moving parts working smoothly and to reduce friction. If the engine is low on oil, the oil is dirty, or the oil pump fails, key parts like pistons, bearings, and the crankshaft can overheat and seize up because of too much friction. That's why this is one of the most common causes of a seized engine.

Overheating

High engine temperatures can cause parts to expand and seize together. Overheating can happen if the cooling system isn't working, there’s a coolant leak, the radiator is damaged, or the thermostat fails. It can also occur during extreme driving conditions or when the engine is pushed too hard.

An accumulation of water

Water isn’t compressible like gasoline, so if it gets into the engine, it can cause it to seize. When water mixes with oil, it can reduce lubrication and lead to corrosion of internal parts. Water can get into the engine in several ways, like through a cracked cylinder head, a blown gasket, or by driving through deep water.

A buildup of rust and corrosion

If a car sits unused for too long, rust can build up and cause the engine to seize when you try to start it. Extended exposure to moisture or humidity, especially during long-term storage, can lead to rust and corrosion inside the engine, which can prevent parts from moving and cause the engine to lock up.

Failure of internal engine components

An engine can seize when internal parts fail or break. Common issues include damaged pistons, broken connecting rods, or spun bearings. These problems can be caused by normal wear and tear, manufacturing defects, or lack of proper car maintenance.

A buildup of oil sludge

Engine oil can cause a build-up of deposits over time that turn into a thick, gel-like substance called oil sludge. This sludge can clog oil passages, stopping proper lubrication and causing engine parts to seize up.

An improper maintenance schedule

All engines experience wear and tear over time. If regular maintenance, like oil changes and filter replacements, is skipped, key engine parts can wear out and eventually fail, leading to a seized engine.

What happens if my engine seizes while driving?

If your engine seizes while driving, it can be pretty scary. You might notice a sudden loss of power and difficulty steering, especially without power assistance. You may also see warning lights pop up on the dashboard and hear unusual sounds like knocking or grinding.

The engine temperature could rise quickly, so you might even see smoke or steam coming from under the hood. Another possibility is that your brake performance can decrease, making it harder to stop the car. These issues increase the risk of accidents due to the loss of control, and depending on the cause, there could be serious internal engine damage. Continue reading to discover more:

My engine has seized up. Now what?

If your engine seizes unexpectedly, don’t try to force the ignition or keep starting the car, as that can make things worse. Shift into neutral and safely pull over to the side of the road.

Once you’ve stopped, turn off the ignition, engage the emergency brake, and call a towing service to take your car to a reliable mechanic. Trying to diagnose or fix a seized engine on your own can cause more problems. A professional mechanic will inspect the damage, figure out what caused it, and recommend the best solution, whether that’s a repair or a replacement.

What can I do about my seized engine?

If a mechanic tells you your engine is seized, there aren’t many options left. In most cases, they’ll recommend replacing the engine rather than trying to repair it since repairs can end up being more expensive in the long run. Sometimes, a replacement is actually cheaper and makes more sense, but it really depends on your car and how bad the damage is. It all comes down to the extent of the problem. Be sure to talk to a qualified mechanic to figure out the best course of action for your engine’s seizure based on your specific situation.

How much does it cost to replace a seized engine?

In Canada, the cost of replacing a seized engine can vary a lot depending on factors like your car's make and model, the type of engine, and how much damage there is. On average, you’re looking at anywhere from $5,000 to $10,000 or more for a basic engine replacement. This typically includes a remanufactured or used engine, labour, and extra parts like gaskets and seals. If your car is newer, high-end, or needs a specialized engine, the cost could be much higher. It’s a good idea to get quotes from a few mechanics or repair shops to get a clearer estimate.

This is why it's so important to keep up with your regular car maintenance, even if the costs add up. Regular seasonal maintenance, like winter car maintenance and summer car maintenance, can help prevent your engine from seizing.

Will car insurance cover the cost of replacing a seized engine?

Your car insurance policy may cover the cost of replacing a seized engine, but it all depends on whether you have the right coverage and what the circumstances are that lead to your engine seizing.

Standard auto insurance, which includes third-party liability coverage and accident benefits coverage, and sometimes uninsured automobile and direct compensation-property damage coverage, will not cover the costly repairs of fixing or replacing a seized car engine.

Even the popular optional types like comprehensive coverage won't cover a seized engine replacement. Optional collision coverage could potentially cover the cost as long as you can prove that the engine seized due to collision-related damage. But, truthfully, what you really need is mechanical breakdown insurance.

Mechanical breakdown insurance (MBI) is an optional coverage add-on that helps pay for repairs when specific car parts fail due to mechanical issues. However, it does not cover seized engines due to accidents or regular wear and tear. MBI can cover a variety of mechanical failures for your car, including engine failures like a seized engine, just as long as it isn't caused by an accident, lack of proper maintenance, or another external event.

Looking for insurance? BrokerLink can help

If you’re thinking of adding mechanical breakdown insurance to your car insurance policy, call BrokerLink today! Our licenced insurance experts are ready to help answer any questions you have about your car insurance policy. We can even offer some tips about the most reliable cars in Canada if you're searching the market for a new vehicle.

And speaking of a new vehicle, don't forget that you'll need to update your car insurance policy as soon as you purchase it. The make, model, and year of your car impact your insurance premium, so if you’re not getting the same car, you’ll need to update your policy or get a new one.

Luckily, getting an updated quote from your insurance provider is usually pretty simple. You can also compare quotes from other insurers by reaching out to them directly or working with a trusted insurance brokerage like BrokerLink. We can do all the work for you by shopping around and comparing the best quotes for your insurance needs.

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