With reference to the engine cylinder compression test, answer the following questions: 5.1.1 Give a reason for conducting the test - NSC Mechanical Technology Automotive - Question 5 - 2023 - Paper 1

1. Dry compression test: Measures the pressure in the cylinder without adding oil.
2. Wet compression test: Involves adding a small amount of oil to the cylinder and then measuring the pressure to assess the condition of piston rings and cylinder walls.

1. Worn or cracked cylinders: Damage to the cylinder wall can lead to loss of compression.
2. Worn or broken piston rings: If the piston rings are not sealing properly, compression will escape, resulting in low pressure.

A – Pressure control valve / knob / regulator B – Gauge / Meter C – Compressor hose / air hose / pipe D – Spark plug connector / adapter / hose / pipe

Pressurised air is blown into the cylinder during the leakage test to identify any leaks within the engine components. By monitoring the pressure and listening for escaping air, technicians can diagnose issues such as leaking valves, worn piston rings, or damaged gaskets.

1. Ensure the inlet hose is not stepped on or restricted in any way to allow for accurate readings.
2. Confirm that the hose connections are airtight to prevent false measurements.
3. Conduct the test in a well-ventilated area to ensure safety and reliability of results.

1. Powertrain (PCM)
2. Transmission (TCM)
3. Engine (ECM)

1. The extent of the imbalance can indicate uneven wear or improper mounting.
2. The run-out of the wheel assembly can cause vibrations or handling issues.

1. Start the balancer and allow the wheel to spin to assess any imbalance.
2. Obtain the imbalance readings and note the locations of the rim for correction.
3. Fit the correct weights on the specified locations of the wheel based on the readings to achieve balance.