How often should you change oil in your car?
There were times when engine oil was recommended to be changed every 3,000 miles. Gradually, car manufacturers have been extending oil change intervals to 5,000 miles, then to 8,000 and in some cases even to 15,000 miles. So, how often should you change oil in your car? Has modern engine technology advanced far enough to eliminate the need for regular oil changes?
Let's get this myth out of the way. Yes, technologies used in modern car engines are improved, but if you took apart an engine in any new car, you would see the same basic design as in any truck from the 50s or 60s: there is an oil pump, crankshaft, pistons and everything is still lubricated by oil. Any super-modern engine will not run more than a few minutes without oil. Longer oil change intervals mostly became possible thanks to dramatic improvement in oil quality. On top of that, many new cars use synthetic oil that lasts longer. Can you drive without oil changes for 15,000 miles or more if you use synthetic oil? This is another myth: yes, synthetic oil does last longer, but as you drive, products of mechanical wear and oxidation contaminate oil and reduce its ability to lubricate moving parts.
The longer you drive, the more the oil filter gets clogged with deposits. A dirty oil filter reduces the oil flow and increases friction. In addition, some amount of oil is normally consumed between the oil changes. If you drove for 15,000 miles without topping up your oil, you would find out that the oil level dropped a lot. A low oil level also causes the engine to wear faster. One reason manufacturers set oil change intervals longer is to lure prospective buyers by "lower" maintenance costs. Should you change oil as often as every 3,000 miles then? Unless you want to see your mechanic every two months, a 3,000-mile oil change interval is another extreme. If you check your oil 3,000 miles after your last oil change, chances are it will still be pretty clean.
Unless you race your car daily, even mineral oil can last longer than 3,000 miles. Most car manufacturers recommend 3,750 to 10,000-mile oil change intervals. Typically you can find two oil change intervals listed in the vehicle's maintenance schedule: the longer interval for "normal" conditions and shorter interval for "severe" conditions. Severe conditions typically include driving on dusty roads, repeated short trips in low temperatures, extensive idling, towing, etc. Even if you drive in "normal" conditions, the best idea is to keep the oil change intervals somewhere in the middle between what is recommended for "normal" and "severe" conditions.
You can find your maintenance schedule in the owner's manual or in the Warranty and Maintenance Guide. Some manufacturers post maintenance schedules online, you can find the links in the bottom of this post.
Many new cars have an oil life monitoring system that will display a message when the oil change is due, however, to work properly the system needs to be reset at every oil change. In addition, an oil life monitoring system does not sense the oil level. You still need to check your oil level regularly and keep it topped up.
Should you change your oil after recommended time interval if the mileage is very low? Car manufacturers recommend to have the oil changes done every 4-6 months or by mileage, whichever comes first. This is typically based on average driving of 15,000 miles per year. If you don't drive a lot and only put a couple thousand miles in 4 months, there shouldn't be a big problem if you change your oil in 5 or 6 months instead of 4. It would be unreasonable for a car manufacturer to deny the warranty coverage if you do your oil changes still within the recommended mileage. However, if you want to be sure, consult with your dealer.
Change your oil more often if:
You use your vehicle to tow a trailer
If your car has a turbocharger
Your daily driving includes mostly short trips
You race your car daily
You regularly drive on unpaved roads
Change your oil less often if:
Oil remains clean when the next oil change is due
You drive mostly on the highway
You use synthetic oil
One way to tell if your car needs an oil change is to check the oil level and condition on the dipstick. See photos in this post: How to check the oil level and how to read the oil on the dipstick