What Is Hydrolocking An Engine? Everything You Need To Know

Are you wondering how a hydro-locked engine occurs and how to fix it? I know it’s never a good idea to get water in your engine. When this happens, your internal combustion engine experiences hydro locking. Several factors can affect how much a repair will cost, from extremely high to very little.

Keep scrolling down because, in this article, we will feature the causes of the hydro-locked engine and how to fix it.

However, you might not always think about the consequences when the circumstance arises. You notice water in a passageway but are unaware that it is four feet deep. The hood of your truck slips below the water as you splash it through a brook. You are besieged as you make a hasty retreat to high ground and hurricane floodwaters quickly rise.

What Causes An Engine To Hydrolock?

The term “hydrostatic lock” is where the word “hydro locked” originates. It’s a situation that involves water, as you might have guessed, which is unquestionably bad news for any automobile engine.

When your engine hydro locks, it signifies that there is too much water in the engine cylinders. Unfortunately, water cannot be compressed by pistons in the same manner that fuel and air can.

Other fluids besides water can result in that hydro-locked condition. Coolant and oil are two more fluids that, if they enter the engine cylinders, will have the same effect.

A flood is one of the most frequent situations where an engine experiences a hydrostatic lock. Sadly, many people are familiar with this circumstance, especially in light of the recent severe flooding that affected various areas of the nation. There is no question that water will fill each of your car’s cylinders and result in a hydro-locked condition if excessive water levels submerge it.

Flooded vehicles after a natural disaster.

Hydrolocking from water can also occur for the following reasons: Taking a car amid a strong storm and through unusually deep puddles. However, it’s vital to keep in mind that other fluids, such as coolant and oil, can also induce hydro locking. These liquids may enter the cylinders if an engine block develops a sizable breach or a head gasket that is beyond repair.

Does Hydrolocking Harm An Engine?

Your car’s engine might suffer a great deal of harm from hydro locking.

To begin with, it’s obvious that water won’t mix well with any mechanical automotive component. When water comes into contact with an automobile engine, the situation is a hundred times worse. Water will speed up the natural corrosive process of metal parts if it is kept in place for too long.

However, hydro locking will harm the engine the most severely when it’s operating. Simply explained, your engine has a lot of little and large moving parts. Most of the harm is done when those moving pieces abruptly cease owing to a hydro lock. Your engine may sustain the following types of damage as a result of hydro locking:

  • rusted bearings
  • damaged crankshaft
  • bending or breaking connecting rods
  • a split in the cylinder wall or head
Crankshaft repair by an auto mechanic.

As you can see, if a parked car becomes hydro-locked, there is already enough expensive damage to be concerned about. If the engine is running while the hydro locking occurs, the damage is even more severe.

You may watch out for a number of warning signals to determine if your engine has a hydro lock. Consider a scenario where you are driving through deep water and the engine becomes hydro-locked while it is already running. In that situation, you’ll have symptoms like:

  • an unexpected engine stall
  • unusual spitting of the engine
  • sounds of banging and knocking
  • restarting the engine is unsuccessful

However, hydro locking can still occur when the car’s engine is off, for example, during a flood. When that occurs, you’ll discover that the engine won’t start at all. Additionally, once you crank the ignition, the engine can make a banging or thumping noise.

How To Fix A Hydrolocked Engine?

An engine that experiences a hydrostatic lock can be fixed. The procedure, meanwhile, can be expensive and time-consuming. The severity of the damage will determine how costly the repair is.

For instance, if the damage is modest, you can repair the engine by replacing the fluids and oils and installing a fresh set of spark plugs. However, an engine with significant hydro locking will need more extensive repairs.

Car engines can hydro lock rather easily, but fixing them is more difficult due to the extensive hidden damage caused by water entering internal combustion engine components.

The water in the cylinders needs to be taken out first. The spark plugs are taken out and then the engine is started. It may be all that is necessary to remove the clogging water in engines that were hydro-locked at idle or when the engine was not operating so taking out the spark plugs is not necessary.

If the water is removed as quickly as possible after the incident, the cylinder walls won’t corrode. The vehicle might be able to start again with a fresh set of spark plugs and an oil change.

You are almost certain to have damaged internal components if the engine was running much above idle when water entered the engine. Every component of the internal combustion engine needs to be removed, disassembled, and checked for damage. Usually, you can find cracked pistons, scored bearings, and bent connecting rods.

Pressure testing the cylinder head and looking for cracks in the engine block are both recommended. To ensure that the crankshaft is not bent, measurements should also be taken.

What Happens When You Hydro-lock an Engine

Hydro-locking an engine can be detrimental to your car. When a piston is not working correctly and cannot be compressed this will cause it not to be able to travel how it should and if your motor is still running when this happens it will cause complete failure in the motor’s mechanics.

One of the reasons a piston may become in-compressible is when the number of liquids that enters a cylinder becomes greater than the volume of that cylinder. When this happens to your motor, you have yourself a hydro-lock engine. The only options you will have to fix your car at this point are very few and both ways are going to cost you a pretty penny.

To fix an engine that has been hydro-locked you will either have to replace the whole engine and get a new one, or you can have a mechanic break your old engine down and rebuild it from scratch.


The topic of hydro-locked engines has been extensively discussed on this page. First, we gained knowledge of what a hydro-locked engine is and the potential harm that it might cause.

The signs of this issue were also discussed. It may manifest as stalling, an inability for the engine to turn over, an audible clicking sound from the engine, and difficulty starting. The causes of this issue were also discussed, including flooding, driving into water, and locking up due to a failing cooling system.

Finally, we discovered how to solve the issue and the associated expenditures. I hope you find this article great and helpful.

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About Brock Rangel

Hi, I am Brock, and I am the lead editor/photographer for TheCarColony. I have been a mechanic for over 14 years now, and I am here to spread my car knowledge across the web!

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