The HD grading signifies the oil's purpose. Here's why it's so important that you do not ignore those letters when you see them on a bottle of motor oil. Read more: 14 Major Tire Brands Of 2025 Ranked ...

The type of oil you need to use in your car is clearly indicated in its owner's manual—and sometimes right on the oil fill cap in the engine bay. It shows the recommended viscosity (the ...

There are a number of ways to tell if motor oil has gone bad, and sometimes it's all about smell. If your engine oil smells like gas, or there is an oil smell inside the car, your motor oil needs ...

While you've probably seen the HD tag on a bottle, those labels don't always convey what the letters stand for: a lubricant graded for heavy-duty use. The HD grading signifies the oil's purpose.