Hydrolocked Engine (Meaning, Causes, & Fixes)

Hydrolocked Engine

The intricate components of vehicles are designed to make them work seamlessly. However, a smooth ride may not always be the reality.

There are times when vital components fail, rendering your car useless.

The purpose of an engine's piston is to compress a mixture of fuel and air. If enough water gets into the cylinder, it can hydrolock, which means all its components will stop moving simultaneously.

The article covers all you need to know about a hydrolocked engine.

What is a Hydrolocked Engine?

The word "hydrolocked" comes from the word "hydrostatic lock." This condition, which involves water, is bad news for any engine.

In a hydrolocked engine, internal movement stops as the engine's components are subjected to excessive amounts of fluid.

If too much water gets into an engine's cylinders, it will cause it to hydrolock.

Unfortunately, a piston can't effectively compress water the same way that it does fuel and air.

Since the fluid is incompressible, the piston inside the affected cylinder can't reach the top of its stroke.

This prevents further movement within the cylinder and stops the engine's rotating assembly from working properly.

The most common cause of hydrolock is accidental water exposure to the cylinders.

However, other factors, such as mechanical issues, can also cause this condition. Other fluids that can cause this condition include oil and coolant.

Depending on the engine's condition, hydrolock can affect vehicles running or resting. In running cars, sudden hydrolock can lead to stalling.

What Happens When an Engine Hydrolocks?

Those knowledgeable about an engine's inner workings will know that water, metal, and fire don't mix well.

Turning your vehicle into a steam engine can result in two problems. One, a massive garage bill, and two, a phone call to the scrapyard to get your car.

Various factors can also cause Hydrolock. Some of these include people driving through puddles and unknowingly putting their vehicles at risk by using a cold air intake system.

To avoid experiencing this type of catastrophic event, it's important to understand the true causes of this condition.

When an engine experiences a catastrophic failure or seizure because of too much water in its cylinders, it is called hydrolocking.

An internal combustion engine is designed to handle the compression of air. On the other hand, water can be incompressible unless a lot of pressure is applied to it.

If the water starts to fill the combustion chamber, rotating the crankshaft will cause the pistons to go up to exert more pressure on the fluid.

Since the reaction force from the water is greater than the stress the components can handle, something has to give.

If an engine is underperforming and has a small capacity, it can seize up and sputter to a halt.

This can also happen when the vehicle runs at a low speed and needs the necessary force to rotate.

This is the least-damaging step, as the engine has to be flushed and turned over to remove the water.

The cylinder head, inlet manifold, and other components should be removed to check for further damage. Changing the gasket could also prevent further issues.

The real damage that an engine can experience is when a large amount of water enters its cylinders.

This can happen when an engine runs at high speed and has a decent capacity. The reaction forces generated by the water will break various components.

The bending of the connecting rods can lead to the need for a new set of connecting rods or an engine rebuild.

If the rods completely snap, the metal shards can bounce around the cylinders and into the crankcase.

Unfortunately, this can lead to the formation of holes in the cylinder head or the sump.

If this happens, the vehicle will likely require a new engine replacement. This depends on the owner's decision to scrappage the car.

Leading Causes of Hydrolocked Engines

A common cause of a hydrolocked engine is when a vehicle is driving through high water.

Most cars have intake systems that have vents near the wheel arch. These vents can prevent excessive water from entering the engine.

When driving through a large body of water, the water can cause the intake to surge up and the air filter to get saturated.

Water can then enter the inlet manifold as the revolutions compress the cylinders until the pistons can't push further.

Another common cause of hydrolocked engines is modifications to the intake system.

For instance, some petrolheads have found a way to fit a cone air filter in the corner of the rear bumper.

This means it can be in the line of fire if the vehicle is driving through water less than 6 inches thick.

The failure of the head gasket can also cause hydrolock. Instead of the cooling chambers around the block to eliminate heat, the coolant will go into the pistons.

This can cause the gasket to split or crack. The thermal expansion of the head gasket can get too fast for it to deal with, causing it to break.

Another rare cause of hydrolock is an injector leak. If the injector is cracked or stuck open, it can lead to the engine becoming flooded with fuel.

How to Fix a Hydrolocked Engine

The amount of water that has entered the engine and the length of time it has been there are some factors that can determine if a fix is possible.

If the RPMs were low and the water was flowing slowly, it could clear the system yourself.

Please get rid of the spark plugs, start the engine, and then rev it while it's in the park. You should also remove one or more cylinders and replace the spark plugs. However, in an emergency, you might be able to dry the plugs instead.

To remove any moisture that might cause corrosion, you should thoroughly clean the cylinder walls. However, this can only be done when you can access a safe space.

If the engine has a lot of water, it might have a hydro-locked issue. In a worst-case scenario, this issue could cost you up to $8,000. If you can't salvage what you can, you might have to replace the entire engine.

What Damage is Done to a Hydrolocked Motor?

The damage caused by a water hydrolock may be more severe depending on the speed at which your car moves.

When water gets into your engine's cylinders when running at a low RPM, such as when you're idle, you may not experience any damage.

However, if you have a hydrolock, you should get immediate assistance to avoid further issues. The engine's inner parts can become damaged and pit if the issue isn't resolved quickly.

If your engine runs above idle, similar to driving down the road, a hydrolock could have catastrophic consequences.

The force behind the moving pistons could bend the connecting rod, crack a part of the cylinder wall, or even cause a fracture in the head of the cylinder. A connecting rod could also break through the engine block if the engine is tilted.

When the engine isn't running, a hydrolock can also occur. The fluid can get into the cylinders, while the starter cannot start the vehicle.

The only damage that can happen in this situation is if the engine's internals gets damaged due to corrosion.

Other types of damage that can occur when a hydrolock occurs include a broken crankshaft, worn-out bearings, and a crack in the cylinder head. Also, connecting rods that get damaged or bend.

If a parked vehicle gets hydrolocked, it could cause costly damage.

However, the damage would be worse if hydrolocking occurred while the car was in motion.

Hydrolocked Engine Symptoms

A dead miss will occur when the engine encounters a small amount of water in the cylinders. If the amount of water is much, a loud knocking noise will be heard as the cylinder fills up.

If it's just a tiny amount of water, the engine might blow through the exhaust, but if more is drawn in, the noise will continue, and the engine will shut down.

Hydrolocked Engine Repair Costs

One of the most common fixes you can try is replacing the engine. It doesn't matter if a new or used one gets installed; the hydrolocked engine repair cost can be around thousands of dollars.

A labor-intensive process that involves hydrolocked engine repair can run from $3,000 to $8,000.

How to Prevent a Hydrolocked Engine

It's hard to avoid hydrolocking, especially if flash floods hit your area. You might need more time to get to higher ground.

In certain situations, you should take the necessary steps to avoid hydrolocking. Some of these include keeping water away from your car's air filter and intake opening and avoiding driving through puddles or deep water.

Contact a mechanic immediately if you think water has gotten into your car's engine.