Make sure to use a high-quality oil filter and crush washer gasket with the drain plug after the car has idled for 20 minutes. Engine oil flushes are especially useful on VVT Subarus and Turbo Subarus.

1st step is bringing the car up to operating temperature. 2nd step is turn off the car and add the engine oil flush. 3rd step is to idle the car for 20 minutes. Finally, complete an oil change.