A diesel machine operator reports a dead cylinder.
What test would you run?
Overflow
Coolant pressure
Cylinder cut out
Blow-by
Cylinder run out
The correct answer and explanation is:
The correct test to run when a diesel machine operator reports a dead cylinder is a Cylinder cut-out test.
A Cylinder cut-out test is used to isolate the specific cylinder that is not functioning properly. This test is usually performed while the engine is running. The mechanic will sequentially disconnect or “cut out” one cylinder at a time to determine if there is a noticeable change in engine performance. If cutting out a particular cylinder causes a noticeable drop in engine speed or power, it indicates that the cylinder is contributing to the engine’s operation. If cutting out a cylinder does not affect engine performance, then that cylinder is likely “dead,” meaning it is not contributing to power production.
Other tests such as overflow, coolant pressure, blow-by, and cylinder run-out might be useful for diagnosing different types of engine issues, but they are not specifically aimed at determining a dead cylinder.
- Overflow tests are typically used to check for fuel system issues, not cylinder function.
- Coolant pressure testing is useful for identifying leaks in the cooling system or potential head gasket failure, which can affect overall engine performance but not directly diagnose a dead cylinder.
- Blow-by measures the amount of exhaust gases passing into the crankcase, indicating internal engine wear, but it won’t isolate a dead cylinder.
- Cylinder run-out checks the alignment or condition of the cylinder, useful in cases of mechanical failure, but not directly for detecting a non-operating cylinder.
Thus, the Cylinder cut-out test is the most appropriate choice for identifying which cylinder is dead and diagnosing the root cause of the issue.