04 Sep, 19

Can A Cracked Engine Block Be Fixed?

When it comes to your vehicle, there are some components that are easy to fix and some that are not so simple fixes. For example, if you have worn brake pads, you can simply replace them. However, having a faulty or cracked engine block… now that’s something you might worry about. Some would say that it’s the end of the world, however, this is not always the case as it depends on the severity of the damage. Below we will discuss the issue of having a cracked engine block, how to diagnose it and what can cause this issue to occur.


What Does It Mean If Your Engine Block Is Cracked?

The engine block, also commonly known as the cylinder block, is the structural framework that supports the components that make up the internal combustion engine. Within the engine block, you will find the cylinders that provide power to the vehicle, cylinder heads and crankcase, which is where the crankshaft is located. The crankshaft is responsible for converting the linear motion of the pistons in the engine cylinders, to rotational energy. This energy provides power to the wheels to get the vehicle going.


Additionally, you’ll find the coolant passages, which helps prevent the vehicle from overheating and oil passages, which serves as a lubricant for the different metal parts of the car engine. Oil reduces friction between the engine components, in turn reducing the risk of the engine overheating.


The engine block is responsible for housing all these components and others, so it is constructed from strong, durable materials. There are two main types of materials that manufacturers use to make engine blocks. Many use solid blocks of cast iron to provide a solid and sturdy platform for the different engine components, however, this can be quite heavy. An alternative that some manufacturers use is aluminium alloy, due to it being lighter and much better at managing heat.


As you can see, the engine block is a vital component and if it becomes cracked, there is a risk of the structural framework falling apart. Fixing a damaged block is not always easy and as mentioned above, it largely depends on the amount of the damage inflicted. Also, the crack may cause other problems to develop, such as excessive heat in the engine and poor engine performance.


How To Diagnose A Cracked Engine Block

If the crack in your engine block is small, there is a chance you won’t be able to spot it. This is why it can be difficult to diagnose this issue by just looking for the crack itself unless it is large and visible to the naked eye. Which is why it’s important to be aware of the issues that are created due to the cracked block. Below are some of the signs that you may notice:

  • Blue or Grey Engine Smoke – If you notice this type of smoke coming from your engine bay, then this can be a big indication that your engine block is cracked. Smoke should only come out of your vehicle’s exhaust system, however, if there is a crack in the engine block, the smoke will just end up escape through that.

  • Engine Overheating – Engine coolant, or more commonly known as antifreeze, may start to leak out of the crack in the engine block. If the coolant is leaking instead of circulating through the engine to keep it cool and at operating temperature, this will cause the engine to overheat. Also, you may notice white smoke coming from under the bonnet, and your temperature gauge will be in the red region.

  • Mixing of Engine Oil and Coolant – If the coolant level is decreasing, it can be due to the liquid leaking through the crack. This could result in the coolant mixing with the engine oil. As you know, oil and water don’t mix, so if they do, you’ll see a white gunky liquid under the engine cap. Since each liquid has its own passage in the engine, a crack in the engine block could potentially cause them to mix.

  • Poor Engine Performance – Cylinders in the engine block produce the power for the vehicle with controlled explosions, which are contained within the walls of each cylinder. So, if this part of the engine is cracked, then some of the energy from the controlled explosions can escape through the break and therefore lead to low engine compression. As a result of this engine problem, you may notice rough idling as well as a reduction in fuel economy.

What Can Cause An Engine Block To Crack?

Knowing the possible causes of a cracked engine block can help drivers understand how to prevent such problems occurring. An engine block does not spontaneously crack and there is often a trigger, such as a minute crack.


When it comes to determining the causes of this issue, excessive heat in the engine is one of the main culprits. Metals are strong, however, not strong enough to withstand very high temperatures, which means some parts of the engine will expand and eventually break. Extreme temperatures can also lower the stress threshold of metals and will make them break easier.


There are different reasons as to why the engine may overheat. Low engine coolant and a damaged water pipe can both cause of this. If the engine coolant isn’t circulating properly because of a faulty water pump, it will not be able to keep the engine cool. In turn, the engine will overheat because the excess heat will not be removed.


Furthermore, excessive heat generation can also be generated from overpowering the engine. Installing a supercharger or a turbocharger that is not compatible with your engine will cause serious overheating problems because these components produce more power than the vehicle can handle.


While high temperatures can cause significant damage, so can cool temperatures. If your engine is subjected to extremely cold temperatures, it can cause the coolant to freeze and push against the engine block, resulting in minute cracks.


How You Could Possibly Fix One

As we have mentioned, a cracked engine block is quite problematic and whether or not you can repair it or not depends on the severity of the damage. In some scenarios, the damage can be too extensive and your engine may need replacing. However, if the crack is not too severe, here are a few common ways that it can be fixed:

  • Re-welding – A professional can attempt to re-weld parts of the block that are cracked to help seal them off. In order to carry out this repair, proper welding rods and an arc welder are needed. However, there is always a risk of the block becoming deformed, and the area may become brittle and more prone to cracking because the block is made out of cast iron.

  • Cold Metal Stitching – Essentially, this procedure involves ‘stitching’ the crack up. Cold metal stitching can be very costly and if it is done in parts of the engine block that are repeatedly exposed to extreme temperatures, it may not last. It is not always secure and can come undone.

  • Cold Welding Patches – The cold welding technique is used as an adhesive which forms a seal in the cracks, or they can come as patches. These are patches that you can apply over the crack, however, this is more of a temporary fix. Similar to cold metal stitching, the patches will be exposed to extreme temperatures and this can cause them to become damaged, which in turn will expose the cracks.

  • Sealing Products – Some products can be put in the car’s cooling system, where over time, the chemicals in the product can form a more permanent seal in the cracks (small ones). However, this method will not work if you have an engine coolant leak.

A cracked engine block may not necessarily mean that you need an engine replacement or rebuild, as it depends on how big the crack is and where it is located. Always seek professional help if you are experiencing any of the issues above.

Tags : Cracked Engine Block, Cylinder Block, Engine Coolant Leak, Engine Issues, Engine Overheating, Engine Replacement.
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