Is Expenditure on engine oil by car service station included/excluded in National Income?

No,

The Expenditure on engine oil by car service station will not be included in the national income as it is a part of the intermediate consumption expenditure.

The value of intermediate consumption is already added to the value of the final goods.

The total value of the car service is the final goods and engine oil charges are already added to it.

Only the value of final goods and services is added to calculate the national income.

if the value of Expenditure on engine oil is also included, it will lead to double counting and inflate the national income.

Thus it is not included in the national income and subtracted from the value of output in the production method while calculating the national income