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4 Signs You Need To Replace Your Diesel Engine Cylinder Head And Causes

Jan 10, 2022 Excavator blog

What Is The Function Of A Cylinder Head?

Your cylinder head is a critical part of your diesel engine. Along with the head gasket, it creates the combustion chamber that allows the combustion process to occur properly.

It also lets air in and exhaust out. Coolant and fuel both flow through your cylinder head. This makes its health vitally important to proper engine function.

3 Issues That Can Cause Cylinder Head Failure

You might notice several key symptoms of cylinder head problems, including high oil consumption, bad fuel mileage, and engine overheating.


Overheating causes one of the most common cylinder head issues—cracking. These cracks often occur between the valves, but not always.


Sometimes, if your engine has high mileage and the valve stems or valve guides are worn out, oil can begin to leak down into the combustion chamber. Improperly sealing valves will negatively affect your combustion, and you won’t get the efficiency you’re looking for in your engine.


Cracks through to your fuel system can allow fuel to infiltrate your engine oil. This contamination can lead to other major engine issues.

These problems, if left unaddressed, could mean serious trouble for your engine. You might even experience a total engine failure.

Often, the best solution is to replace your cylinder head. You have a few options when it comes to replacing your cylinder head. Highway & Heavy Parts can help you find the best solution for your diesel engine problems.



As we mentioned, cylinder head cracking is a common issue, and it can lead to other problems. Excessive heat causes the head to expand and contract, which leads to cracking. Depending on the model, the head is sometimes made of a different material, which can make this problem worse.

If you have a crack in your diesel engine’s cylinder head, it could reach your coolant passages, allowing compression gases from the combustion cycle to fill those passages. This displaces the coolant, which causes the head to overheat in certain areas.

This overheating tends to crack the head even worse.


You might also notice a decrease in your diesel engine’s fuel economy. This could be caused by improperly sealing valves, leading to incorrect pressure in the combustion cycle.

In cases like this, you’d be putting significantly more fuel in the engine to get the same amount of power.


Sometimes the valves and valve guides will wear, or seals will come off or get dislodged (knocked or forced out of position), allowing oil to enter the intake or exhaust ports, which causes high oil consumption.


White smoke can also be an indicator of cylinder head problems. In extreme situations, white smoke can come from the diesel engine itself, indicating that coolant has contaminated your oil due to a cracked or damaged head.

It could also indicate exhaust gases escaping through the cylinder head, which signals the need to replace it.

It’s important not to ignore these warning signs. While these symptoms might indicate issues other than your cylinder head, don’t assume it’s not your head. Be sure to evaluate the health of your head to try and prevent catastrophic engine failure from costing you even more time and money.