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Symptoms of a Locked Engine

Initially, it might seem like your engine is seized. When you try to start your car, your engine won’t turn at all. However, that’s just one cause of a locked engine. It’s one of the most common and perhaps the most expensive to repair, but there are other conditions it may also be.

On the day when you least expect it, you start the car and suddenly hear an unusually loud clunking noise. Your car shut off and won’t start, The tank is full and the battery is relatively new. Odds are, the engine seized! What do you do now? You can always sell your car with CarBrain, or find out more about locked engines below.

So what happens if your engine locks up? How do you know if your engine is locked up? Can a seized motor be fixed? More importantly, how do you unlock a seized engine? When your engine locks up while driving, all of these questions will be running through your mind. In this article, we'll try and outline the signs of a locked engine, engine lock up causes, and fixes.

Is it worth fixing a seized engine?

The first step is to determine whether the issues are severe or not. If the repair requires a quick fix, then go ahead and get that car fixed. When a vehicle has a seized or blown engine, the cost of repair could potentially exceed the vehicle's value. To avoid overspending on repairs, it's important to make the right decision and sell the vehicle AS-IS for the best offer possible.

What is a Seized Engine?

What is a Seized Engine?An engine seizes up due to mechanical failure, usually associated with oil starvation. When an engine runs out of oil or the oil isn’t circulating as it should, internal metal parts rub against each other, creating enormous amounts of heat from the friction. Bearings that are meant to allow for smooth movement grind against the crankshaft and camshaft, sometimes literally welding themselves onto other parts.

What happens when an engine locks up while driving? It will suddenly sound rough and stop on its own. Seized engines due to lack of oil can range from a little engine damage to major damage.

An engine can seize from not running, too. In that case, it’s a little different. The piston rings ‘freeze’ against the cylinder walls from rusting. This is most commonly seen on old cars that are due for restoration.

Hydrolocked Engine

Hydrolocked EngineAn engine hydrolock occurs when water gets into the engine’s combustion chamber. On the combustion stroke, the piston is unable to reach the top of its stroke because the water won’t compress like the air-fuel mixture would. The engine suddenly stops. If the engine is at low RPMs, you may escape without critical engine damage. At higher RPMs, bent connecting rods and busted pistons are almost guaranteed.

Vapor Locked Engine

This one’s a little different. Vapor lock doesn’t mean your engine doesn’t turn over, but your engine won’t start. Vapor lock is a fuel system problem, usually found on older cars with low-pressure fuel systems. When gasoline in the fuel lines or fuel pump turns from liquid to gas, it starves the engine of fuel and it stops running. When a vapor lock occurs, your engine will begin to sputter and lose power, then turn off. It won’t start no matter how hard you try.

Should I fix my car or Sell it As Is?

Should I fix my car or Sell it As Is?

What Causes a Locked Engine?

What Causes a Locked Engine?For a bad starter, common engine seized symptoms include infrequent oil changes and running the engine out of oil. It could also be a broken engine oil pump or a sudden engine failure.

For a hydrolocked engine, you’ll know its cause when it happens. It’s due to water getting into the engine through the air intake, probably from driving through a deep puddle or floodwaters.

For an engine vapor lock, it’s almost always related to extreme heat. What happens is the fuel in the lines between the fuel pump and the engine turn to fuel vapor. It can be from sitting in traffic in sweltering heat or from turning off your engine when it’s hot out, and the fuel temperature quickly rises. The fuel pump can’t move fuel vapor and the pump cavitates. Now, can you "unseize an engine from sitting"?

What to Do When Your Engine Locks Up

If your engine locks up when you’re on the road, put your transmission in neutral and coast to the side of the road. If it happens when you're already parked, you’re not going anywhere. Try turning your engine over once or twice. If it doesn’t crank, don’t keep trying. You could burn out your starter or cause more problems.


How to Free a Seized Engine

Treating a locked up motor depends on its cause. You can tell if your engine is locked by trying to turn the crankshaft with a breaker bar. If it turns, the engine isn’t seized, and you should look for a different cause.

  • If your engine has seized up while you’re driving, there’s nothing you can do about it short of an intensive engine repair or replacement.
  • If you have an engine that seized from sitting for a long time, pull the spark plugs out of all the cylinders. Fill the cylinders with engine oil and let it sit for a few days. Then, try turning the engine over with a breaker bar. If it moves, you may be able to salvage the engine. If not, you’ll have to pull it apart and rebuild it.
  • If your engine is hydrolocked, take out the spark plugs right away and crank the engine over. The water will pump out of the cylinders, releasing the hydrolock. That’s IF there are no damaged parts inside.
  • For a vapor locked engine, you need the fuel to cool to the point of condensing. It can happen frequently just by letting it sit and cool off. Or, if you need to get it going right away, you can cool off the fuel pump and lines by splashing cold water or ice on them, condensing the vapor back to liquid.

My Engine Locked Up - Repair Cost Averages?

My Engine Locked Up - Repair Cost Average?A vapor locked engine requires no cost to repair if you’re able to cool off the system quickly. If the fuel pump has overheated, you can expect it to cost $500 to $1500 for a replacement.

An engine hydrolock could be as little as the cost of new spark plugs and an oil change. Or, if the engine was damaged when the hydrolock happened, you may need to replace the engine at a cost of thousands of dollars.

In short, if you have an engine that seized, repair costs will probably be high. The same is true if your engine is locked up — costs will probably be higher than you care to pay for on your own.

If you want to know more about engine damage, we created a guide on blown engines on various makes and models of cars throughout the years you can check out.

Can a Seized Engine be Rebuilt?

If an engine is seized due to oil starvation, you might be able to rebuild the seized engine, but the labor costs can reach epic heights. A mechanic will have to inspect your engine to make sure no major irreparable damage was done, and particularly that a rod hasn't gone through the engine block. Another thing to look out for is the overheating of an engine after it seized. The heat can warp parts of the engine you won't be able to see, so it might be more costly than initially expected. It's probably better to explore options of selling a car with engine problems.

Seized Engine Fix Costs

If the engine has seized and needs a rebuild or replacement, it could easily become $3,000 or more for your repair.

If you can’t afford the expense and downtime a locked up motor comes with, let us get you out of it. At CarBrain, we will make a guaranteed offer for your car in as-is condition. If you accept our offer, we’ll come to pick up your car as it sits and put money in your pocket on the spot.

Need answers? Get FREE advice from our client care experts NOW!

Frequently Asked Questions

What Causes A Seized Engine?

Some of the most common reasons an engine seizes include:

  • Lack of Oil/Lubrication
  • Infrequent Oil Changes
  • Sitting for Too Long
  • Water Got Into the Engine
  • Running the Car in Extreme Heat

A seized engine can be extremely difficult to fix!.

Can You Fix A Seized Engine?

You can most certainly fix a seized engine, but that will all depend on what the issue is.

If you have recently driven through a deep puddle, you can remove your spark plug, fill it up with oil and let it sit for 24 hours. After the car sits for 24 hours, you may be able to unjam it with a breaker bar.

If your engine seized because it’s been sitting too long, pull the spark plugs out of all the cylinders. Fill the cylinders with engine oil and let it sit for a few days. Then, try turning the engine over with a breaker bar. If it turns over, you may be able to salvage the engine.

If your car is vapor-locked, you will need to let the car sit and give it time to cool down. If you are in a rush, you can pour a coolant (ice cold water is a popular choice) down the fuel pump lines.

If these solutions don’t work or if your engine locks up while driving, then you have a much more serious issue that will require a mechanic.

What Is A Seized Engine?

A seized engine is an engine that cannot properly work because it either has damaged parts or a lack of oil. If you catch the issue early enough, you can mitigate or even avoid the damage that could be done to your engine. Fortunately, you can trade a car with a bad engine.

How Much Does It Cost To Fix A Seized Engine?

That depends on the issue with the blown motor. Some repairs (like overheat issues or hydrolocks) can cost less than twenty dollars and can be done yourself. More serious issues will cost anywhere between $500 and $3000 and require professional attention.

What Are The Signs Of A Seized Engine?

Here is how to know if your engine is seized:

  • Suddenly stopping while in motion.
  • The vehicle tries to turn on, but it does not.
  • Consistent knocking sound
  • Increased exhaust outtake
  • Check Engine Light Turns On

If you have a damaged engine, you may be facing hefty repair bills. In some cases, the best option in this case is to sell your engine-locked car and get a replacement vehicle.

Can You Trade In A Car With A Seized Engine?

Yes. There are plenty of options for trading in your car with a seized engine: from dealerships who will repair and resell your vehicle to junkyards who might just part it out. A seized-engine isn’t a death sentence to any trade-in dreams.

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