Engine oil is vital for protecting a car's engine. If your car requires 5W-20, can you use 5W-30 instead? Here's why those numbers are so important.

10W-30 and 5W-30 are interchangeable in hot climates, as they are identical once warm. However, owners should stick to the recommended oil in cold weather.

Engine oil is vital for protecting a car’s engine. If your car requires 5W-20, can you use 5W-30 instead? Here’s why those numbers are so important.