signs of a cracked engine block

What are the Signs of a Cracked Engine Block

A car’s engine block is made of aluminum or cast-iron casting that acts as the bottom portion of the engine. The block acts as the base for the cylinder head(s) and other major components of the engine. The engine block houses the crankshaft, pistons, connecting rods, and (in some cases) the camshaft. The block and its internal components are referred to as the “bottom end” of the engine. And the cylinder head(s) and related parts are considered to be the “top end” of the engine.

The engine block is the main component of an internal combustion engine, that generates the power by igniting a fuel/air mixture to produce an explosion and cause the vehicle to drive. In a properly functioning engine, the piston inside the cylinders moves up and down, turning the crankshaft and allowing the wheels to move. Engine blocks of a vehicle are designed to last for a lifetime, but unfortunately, things can and do go wrong that lead to the formation of cracks in the engine block.

It is bad news to have a cracked engine. In the world of automotive repair, it is one of the most costly and serious problems that you may encounter. It can often be mistaken as a cracked cylinder head or blown head gasket due to having the same kind of symptoms. But a cracked engine is far worse than these problems. This means your car requires a new engine. To be able to spot signs of a cracked engine does not need for you to be a trained auto mechanic rather you can do it on your own if you have the right skills and awareness.

Common Signs of a Cracked Engine Block

It is uncommon to have a cracked engine block. The cylinder head(s) usually crack and start causing problems long before the block does. But there are instances where a block can crack, resulting in some of the following symptoms.

1 – Overheating

On your car’s dashboard, there is the engine temperature gauge connected to the coolant temperature sensor. You must keep an eye on it while you’re driving. When an engine block is cracked it results in a coolant leak (either internal or external) and prevents the proper circulation of the coolant through the engine. And as a result, the engine can start to heat.

Under normal circumstances, the needle on the gauge doesn’t show an increase in the temperature until the engine had time to warm up. During summer, this might happen within a couple of minutes while in winter it could take ten minutes of driving to show the rise in the temperature. Most engines run at between 85 and 100 degrees Celsius. And anything that is considered too hot for the motor will be shown as the red range on the gauge. So, if you see the needle in this area, know that the engine is overheating. Immediately, pull over and switch off the car to allow it to cool.

2 – Coolant Issues

Coolant can leak from various points in the system, like the rubber hoses, the clamps, the water pump, or the radiator. A coolant leak can also occur inside the engine block or through cracks.

When the engine’s cool, check the coolant level by looking at the header tank and top it up with the right kind of coolant. Take your car for the run and notice if the temperature continues to rise. If it does, it is an indication of the underlying bigger problem.

3 – Head Gasket Problems

When your head gasket blows, there will be terrible performance in a check engine light, limp mode, oil, and coolant mixing. There will either be oil in the coolant or a milky-like substance in the oil. This is another symptom of a cracked engine block.

The reason why an oil and coolant mix is that the gasket is unable to keep the liquid flows confined to their respective channels. Hence, they are free to splash around and end up in the wrong places while they pass between the block and the head.

4 – Coolant or Oil Leaks

If you notice a small or large puddle under the car and its oil or coolant, then it is not a good sign. An oil leak can most likely happen from an oil filter, drain plug, or anywhere with oil flow, including a channel within the cylinder block. A cracked engine can cause an internal or external coolant leak.

5 – Smoke From Under the Hood

There are coolant passages that run through the engine block. A crack in the block may cause the leakage of coolant from the passages into one of the engine’s cylinders. The burnt coolant on the engine’s cylinder causes combustion, resulting in the white smoke/steam coming out of the vehicle’s exhaust pipe.


The performance of a car is severely affected when there is a cracked engine block, and the car struggles to start. It can be dangerous to ignore the signs and continue to drive. You should take immediate steps as soon as you notice any common signs mentioned above and stop the car to prevent it from any further damage.

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