Home Diagnosis and TroubleshootingEngine Problems Hydrolocked Engine – How It Happens And How To Avoid It?

Hydrolocked Engine – How It Happens And How To Avoid It?

by Jordan Harris
Hydrolocked Engine

Have you driven through a large puddle and you are asking yourself if you have a hydrolocked engine? If this is the case, and you are in this situation, then you are at the right place because there will be a lot to cover on this topic where we will learn everything about hydrolocked engines.

Having a hydrolocked engine is not a good thing. This means that there is water inside of the engine and is potentially locked or full of water. Resulting in the inability of the engine to function right and the need for the engine to be repaired or replaced.

That’s why you need to watch out where you drive and how you tackle big puddles or start engines from cars that have been in a flood. When water gets into the engine, this is not good news for nobody. Mostly because these engines are really expensive to fix and you will have big trouble sorting the problem out. But more on that later in this article where we will elaborate on the costs involved in fixing the issue. So, what we are going to cover in this article?

We will start from the ground up, by first learning what is a hydrolocked engine. Then we will cover the symptoms of a hydrolocked engine as well as the causes for this problem. Later we will see if this engine could be saved and what you could do about it. So, if you want to learn more, follow along.

What Is A Hydrolocked Engine?

Before we delve into more complex topics like the symptoms and the causes, let’s discuss what is a hydrolocked engine in general terms. This will be quite useful for beginners who are not into cars and want to learn more about the basics of this issue. If you feel like you are more experienced, you can move to the following chapters where we will elaborate on the causes and solutions. If not, keep up with us for a bit.

As you probably know, internal combustion engines are designed to run with fuel. The pistons are compressing the fuel to air mixture and the spark plug is igniting this mixture to create power. Without proper fuel to air to fuel mixture, the car will not be able to run.


Now let’s imagine that you pour water into this mixture? What will the water do? As we all know, water is not a flammable liquid. But a liquid that kills the flame.

So, when a good amount of water gets into the cylinders, the engine will simply stop working. Or get hydrolocked as we noted.

This engine in this situation is permanently damaged. But what type of damage could happen when water gets inside of the engine? Well, that’s what we are going to cover later on.

The important thing is that this engine is no longer able to run. Unless it is opened and repaired. Even though, sometimes these engines end up at auctions and rust from the inside. So, the eventual fate will be for these engines to be scrapped and replaced. Mainly because of the slow response time and the damage of the internals of the engine.

But what are the possible damages that could occur when you have a hydrolocked engine? Let’s see up next.

Engine Damage From Hydrolocking

We learned what is a hydrolocked engine. Something that will be quite interesting for beginners. Now before we discuss the symptoms and causes for this situation to happen, let’s see what engine damage will be done in this situation. Namely, what will be the consequences of water getting inside of your engine causing it to hydrolock? Let’s elaborate on them.

The first thing that will happen if the engine runs like this would be damage to the cylinder walls. These walls will easily get scarred whenever there is water inside some of the cylinders and the engine is having to move the car just 50ft.

Imagine that you go through a big puddle and water gets sucked into the cylinders and you keep driving. If you do so, the water will eventually damage the cylinders and will make them unusable.

The second most probable thing is bent or broken piston rods. Whenever there is water in the cylinders and they lock, if you push the engine as we elaborated in the previous example, the engine piston rods will get bent. Once the piston rods get bent, the engine is simply done. That’s why running a car after it sucks water is not good. These flooded and locked engines will probably never be able to run again.

The third engine damage that could be caused by water damage is rust. As you know, even the engine is made of aluminum, there are still some components like the crankshaft, camshaft, piston rings, and rods that can corrode and ruin the engine. This rust development happens almost instantly because the engine has water in it and the metal is exposed to the water. Now let’s cover the symptoms of a hydrolocked engine.

Symptoms Of A Hydrolocked Engine

Now after we learn the damage that can be done because of water. Let’s discuss the symptoms of a hydrolocked engine. What are the symptoms that you will notice and be able to tell if this engine is indeed locked and does not want to start? Let’s elaborate on these in the following chapters in detail and see more about the symptoms.

1. Stalling After You Drove Into Deep Water

The first symptom of a hydrolocked engine that we are going to cover is the stalling issue. As we already discussed. If you decide that you drive in deep water and hope for the best, the end result will be the same in most situations if the engine of the car is positioned really low.

It will be really easy for the engine to suck water and ruin itself. When this happens, you might be able to move for 50 to 100ft but the car will eventually come to a halt and you will have to call a tow truck to tow the vehicle to the nearest shop to get it diagnosed properly and hopefully with crossing your fingers be able to run again. Which is highly unlikely if this situation happens. But if it’s a mild case, it might work, who knows. Now let’s move to the second symptom.

2. The Engine Doesn’t Turn Over

Another symptom that will also happen when you have a hydrolocked engine, and that is the inability of the engine to turn over. But what does this means in the first place?

Well, it means that the engine is locked. So, if you try to turn over the crankshaft with a socket wrench, the crankshaft will not like to move at all. Meaning that the engine is frozen completely and will not be released until it is completely disassembled and repaired.

This is often useful when you are out there on car auctions and looking for vehicles that were flooded. You can test the engine like this if it spins. If it’s not spinning, then this engine is not salvageable at least not for the right amount of money to be economically feasible.

In most cases, it is a much better idea to purchase a used engine than repair a flooded one. Now let’s move to the last symptom of a hydrolocked engine.

3. Click Sound Only When Trying To Start The Engine

Another symptom of a hydrolocked engine is the clicking sound that you hear when you try to start the car. So, why does this happen?

Well, this happens because the car is full of sensors and it basically can tell when there is something wrong with the engine itself. So, in order for the engine to avoid further damage to the starter and the cylinders, it is deactivating the ability to crank the engine. So, hearing a click-click sound will be there, even though the engine has battery power and you might be thinking that you will be able to start it. But actually, you cannot because of this.

Which is a good thing, don’t get me wrong. The engine has to be opened and checked before you try to start it. More on that we will cover in a bit. Now let’s see the cases when hydrolocked engine situation can occur.

Causes For A Hydrolocked Engine?

Now let’s dive into the causes for hydrolocked engines. We will learn what are the situations that can make the engine lock itself and not be able to start.

Hydrolocked Engine

Knowing the causes will help you because you will be able to avoid a situation like this and end up with a flooded engine that doesn’t want to turn over. Not to forget the great amount of money that you will save by doing so. So, what are the causes? Let’s elaborate on them.

1. Driving Into Deep Water

Driving into deep water is probably the first cause of hydrolocked engine. Many people make wrong calls and unfortunately, this cost them a lot of money to fix.

You just cannot drive a sedan into deep water without thinking twice. The airbox sits relatively low on these cars and this will cause the water to get inside of the airbox and soak up the air filter.

If there is too much water, there will be water beyond the air filter and into the intake. So, imagine that your intake is something like a vacuum cleaner that collects air so the car will run. Now, this intake collects water and this water gets inside of the intake and goes to each of the cylinders.

A small amount of water will evaporate quickly. But if the water is too significant. You will get a hydrolocked engine. So, really beware of heavy rain and deep water. You just never know how deep it could be. Sometimes it is better to turn your car around and try a different route than to go all-in on this and ruin your engine. Now let’s move to the next cause.

2. The Car Was Flooded

Another very probable cause for hydrolocked engines is flooding. And by flooding, I mean not driving through a high level of water. But flooding that was caused while the car was parked.

If you live in an area where are regular heavy rains and floods, it is best to be aware of this problem and act accordingly. This means, do not park the car in a garage that is at an incline because water naturally will fall down and slowly flood the car.

Or in some cases, cars can get into hurricanes and the water levels get high even if you park them on the street. Both of these situations are bad for your car. Meaning that your vehicle will get flooded and the engine submerged underwater.

Luckily if only the airbox is affected, you will be able to clean it off and replace the filter. But what happens is that people whose vehicle airbox was flooded try to start their cars. Resulting in a hydrolocked engine. So, it is an important thing that you should not do that by any means. Don’t start a submerged vehicle if you don’t want to destroy the engine.

3. Coolant Entered In The Combustion Chamber

Another reason for a hydrolocked engine is the coolant that is entering inside the combustion chamber. Yes, that’s right. Coolant can also destroy your engine from the inside. Even though it is there to cool the engine down and avoid overheating issues. So, how does this happen?

Well, this happens because of a major failure of the head gasket. Head gaskets can fail and develop small leaks that will make your engine lose the coolant little by little.

Sometimes though, the coolant can completely hydrolock the engine. If there is too much coolant at one point in a certain cylinder, meaning that the gasket fails altogether. It will hydrolock the engine.

When you disassemble an engine like this, you will notice how there is coolant in one or two cylinders only.

This is really caused by head gasket failure. Luckily, these failures sometimes can be fixed and the problem can be solved. But if there is also a major crack in the block where the coolant passed through, then this hydrolocked engine is destined for the junkyard.

So, beware of these overheating issues and when you notice how the engine overheats. It is important to act quickly and try to solve the problem as soon as possible. If not, you will need a new engine. Now, let’s see in the following chapter if a hydrolocked engine can be saved.

Can A Hydrolocked Engine Be Saved?

Now let’s see if a hydrolocked engine can be saved? And the answer to this question is that it really depends on the type of hydrolock and the extent of the damage inside of the engine that was created during this process.

Let’s say that an engine was only submerged underwater. In this case, the engine could be saved if proper work is performed. But it needs to be performed quickly enough so the engine does not rust from the inside out. The whole engine has to be disassembled in pieces and cleaned from the water that was inside.

If an engine was run into a big pond and water was sucked into the engine and was driven like this for a while. Then this engine probably could not be saved.

Mainly because the engine ran like this and there is damage to the internals of the engine. The rods are probably bent and the pistons locked up. In this case, you will highly likely need a completely new engine to purchase. But more on that later on. Now, in the following chapter, we are going to cover you can try to save a hydrolocked engine and revive this motor. So, how it is done? Let’s see up next.

How To Save A Hydrolocked Engine?

So, how you can save a hydrolocked engine? It really depends on the damage and determine if the engine wants to turn over. If it doesn’t want to turn over, here’s what you will need to do.

The first thing you will need to do is to remove all of the spark plugs and suck the water with a syringe from the cylinders and make sure that there is no water inside of the cylinder.

The next thing you need to do is to drain the oil. The oil inside will probably look like a milkshake substance. Let it drain completely and make sure that you clean everything you can.

Hydrolocked Engine

The next thing you will do is to get Marvel Mystery oil and pour this stuff into each of the cylinders. Let it soak for a day or two. This oil will prevent corrosion as well as will make sure that you will be able to release the pistons.

Then after a day, try to turn over the engine. You can do this by getting a socket wrench and a big pipe to have some leverage. It might not want to release at first. But after some persistency, the engine will be released.

After the engine spins freely, remove the Marvel Mystery oil and pour engine oil into the car. Turn the engine over a few times so the oil goes everywhere around it. Then you can try starting the car. It should start with no big problems. No more hydrolocked engine.

Just beware that not all engines are like this and some can have worse damage and will require complete disassembly and machine work to get them in the right condition.

Cost To Fix This Problem

Now let’s see how much it will cost you to fix a hydrolocked engine. And to be honest, it is not cheap. Not cheap at all. Mainly because when engines get hydrolocked, they are not repairable and it will be a real pain to get them going once again.

So, when this happens, and let’s say the engine doesn’t have mechanical damage inside, you will be able to get it running for $900 or a bit more in some situations. Mainly because the engine needs to be flushed of the fluids. The oil needs to be replaced, etc. There is a lot of work in this so it can cost a bit of money. If you do it by yourself, you will probably get the cheapest deal.

If it’s not savable, then this means that the engine needs replacing. For this, you will need to find a replacement engine and this could cost more than $3,000. Which is not cheap. That’s why it is best to prevent the problem of hydrolocked engines from happening. And how you can do that? Let’s see up next.

How To Prevent This Hydrolock From Happening?

Now let’s see how you can prevent having a hydrolocked engine. What you could do to prevent this?

The first thing you could do is to be aware of your surroundings and whenever you notice a big puddle of water that looks threatening is to avoid it at any cost. Turn your car around and find another route. This way you can be sure that your engine will not get hydrolocked.

Also, watch out where you park your car. You never know when there could be a big storm that could flood everything. It’s always best to park your car on an incline if there is an inclined road available. This way your car will be sure that it will not get flooded and there will be no hydrolocked engine problem

Conclusion To Hydrolocked Engine

In this article, we have covered quite a bit when it comes to the problem with hydrolocked engines. First, we learned what a hydrolocked engine is and the possible engine damage from locking itself.

Then we covered the symptoms of this problem and how it is represented. It could be represented by stalling, the inability of the engine to turn over, clicking sound from the engine, and inability to start.

Then we covered the causes for this problem, which were flooding, driving into water, and locking up because of cooling system failure.

Lastly, we learned how to sort out the problem and the costs involved in this work.

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