Which of the following is NOT part of an oil change service?

In the context of an oil change service, the primary tasks involve replacing the used engine oil and the oil filter, as well as ensuring that the oil level is adequate after the new oil is added. Changing the oil filter is essential because it helps remove contaminants from the oil, ensuring the engine runs smoothly. Adding new engine oil is obviously critical, as it lubricates the engine components. Checking the oil level after the change is important for verifying that the correct amount of oil is present for optimal engine operation.

Testing the pH level of the coolant, however, is not related to the oil change service. This task pertains to the cooling system maintenance, which is separate from an oil change. Coolant pH testing assesses the condition of the coolant, helping to identify issues that could affect the engine's cooling functionality. Therefore, option C does not belong in the list of standard procedures included in an oil change service.