Most people that drive a car in an urban part of the US have to pass an emissions test at least once a year in order to renew their vehicle registration. While this may protect air quality, it can be a hassle if your car is struggling to pass. Did you know that changing your oil regularly not only helps reduce wear and tear on engine parts, but also has an important impact on your emissions test?
General Maintenance for Emissions Control
Like the rest of the car, your vehicle's emission system must be maintained to function correctly and pass annual testing. Let the air intake fill with dust or fuel up each time with the wrong grade of fuel and your vehicle's emission sensors can become dirty or break. This also extends to the oil that lubricates the engine. If the oil is old and worn from overuse, it becomes contaminated and causes wear to parts rather than protecting them. This may reduce compression or increase the risk of overheating over time. The car's computer has to adjust fuel ratios due to these changing conditions. The new fuel ratio may result in more emissions than are allowed by the test, even if your car seems to be running the same as it always was.
Old Oil Increases Emissions
Modern engines also channel oil fumes directly to travel out of the engine via the exhaust system. The Positive Crank Ventilation system is responsible for this process, helping combust those fumes so they don't escape the tailpipe. However, old oil releases more hydrocarbons than fresh oil. This has a direct chance to cause the car to fail an emission test. The easiest way to prevent this specific issue is to change your oil right before a test. If you are right on the edge of passing an emissions test, the change made by putting in fresh oil may be what makes the difference.
Stay on Schedule and Invest in a Timely Change
An oil change right before the emissions test is a good idea, but it won't overcome the effects of ignoring regular changes. Keeping the engine and emissions system in good shape is far more important than just one oil change right before the test. Yet it's still a useful tip to improve your chances of passing just by timing your latest oil change and emissions test to coincide.
Don't return multiple times just to pass your emissions test due to oil issues. Stay on top of oil changes based on the manufacturer's recommendations in the manual to protect the emissions system of your vehicle.