Using the correct type of oil is equally important. If your 6.7 Power Stroke is a workhorse like most diesel trucks, Ford suggests Motorcraft 5W-40 fully synthetic oil regardless of the ambient ...

One last note — we've linked five-quart jugs of 5W-30 Full Synthetic oil with our descriptions, but it's important to note what weight and amount of oil is required for your specific vehicle.

API has a full list ... in a bath of oil. A lower number is better before the W for cold-weather performance, so a 5W oil is typically what's recommended for winter use. However, synthetic oils ...