Cylinder Head Failure-Analysis of Diesel Engine

Cylinder head failures are one of the usual problems for every engine. It happened when the oil leaks between the cylinder head/block and liner body. But shall you directly call the pro for it? Before that, Don’t panic! COOPAL will tell you how to Keep Calm and Check the engine, and if it’s possible to do, Let’s repair!

Cylinder headliner failures typically fall into three categories:

A combustion seal failure occurs when combustion gases leak between cylinder gasket and liner combustion flange or between combustion chamber flange and cylinder gasket. Leaking gases can enter adjacent cylinders, enter into coolant or oil path, or leak outward.

Coolant or oil seal failure occurs when oil or coolant leaks between the cylinder head and liner body, or between the cylinder block and liner body. The oil or coolant may leak into an adjacent coolant or oil pathway, or outward.

Cylinder Headliner-Diagnostic Procedure

The following diagnostic procedure should be performed when cylinder head gasket adhesion failure is suspected or does occur:


Before starting or disassembling the engine, visually inspect the machine and if the following reasons are found.

If there is leakage of oil or coolant at the cylinder head gasket seams or adjacent surfaces, especially at the corners directly behind where the gasket meets.

Sample Analysis

Further sample analysis of coolant and oil.

Check and Test

If the engine can operate safely, start to warm up the engine. Check all possible locations for leaks according to the previous instructions. Using the correct test and measurement equipment, check if the following have occurred.

Shut Down and Recheck

Shut down the engine. Recheck the crankcase, radiator, and overflow tank for significant differences in level, viscosity, or appearance from standard values.


Compare the conclusions from observations from the above steps with the corresponding diagnostic procedures. If the diagnostic evaluation and observations provide clear evidence that combustion gas, coolant, or oil leaking is from the cylinder head gasket sealing, the cylinder head must be removed for inspection and check the gaskets assembly.

Cylinder head gasket inspection and maintenance sequence

Cylinder Head Failure
Cylinder head gasket inspection and maintenance sequence

A – Combustion Seal (Flange)  B – Gasket Body  C – Front End of Engine

Cylinder Headliner-Inspection Procedures

Following inspection procedures are recommended for cylinder head gasket sealing failure or disconnect the cylinder head.

Historical data

View historical data by machine operation, maintenance, and repair, as well as diagnostic data. Make a note of all areas that require further inspection and analysis.

Rocker Cover

Remove the rocker cover and check if oil leaking to coolant contamination.

Record the Torque

Before removal, record the torque of the cylinder head cap screw. After removing the bolts, check the difference in cap screw length.

Remove the Cylinder head

Remove the cylinder head with proper lifting equipment to prevent damage to the cylinder head gasket. (Refer to “Removing the Cylinder Head” section in this chapter.)


Observe the surface of the removed cylinder gasket.


Inspect cylinder heads, cylinder bodies, and liners for leakage of combustion gases and fluids before cleaning components. Inspect cylinders and valve passages for unusual deposits.


Clean the cylinder – Clean the cylinder head – Clean the bushings – Clean the bushings.


Cylinder block –Check if the surface is flat, clean or any damage

Cylinder liners –Check that the bushing flange is flat, Check the flange for damage.

Cylinder head cap screws–Check the thread condition, Check the length.

Determine and repair

After completing the inspection and measurements, determine the most likely cause of the failure of the connecting elements. Make any necessary repairs to the connection components, cooling system, and fuel injection system.


Reassemble the engine according to the procedures and specifications in the appropriate maintenance chapters of this manual.

We provide Cummins Cylinder Head with Genuine Price! For more info of Cummins engine cylinder head, please contact us with part No. or part name plus engine serial No!

Click Here to see our Product!

Leave a Reply

Your email address will not be published. Required fields are marked *