How often should you change the oil in your car?

Updated: March 14, 2020
Car makers recommend different oil change intervals for different cars; typically between 5,000 and 7,500 miles or between 4 and 6 months, whichever comes first for normal driving conditions. Recommended oil change intervals for severe driving conditions are usually shorter: 3,500-5,000 miles or 3-4 months.
Clean versus sludged up engine Changing oil regularly helps keep the engine clean inside and prolong its life.
Severe conditions include driving on dusty roads, repeated short trips in low temperatures, extensive idling, towing, etc. We recommend keeping the oil change intervals somewhere between what is recommended for "normal" and "severe" conditions:

Change your oil more often if your car has a turbocharger or if you notice that the engine consumes oil or if you like spirited driving or use your vehicle for towing. Change your oil less often if you use premium synthetic oil, keep the oil level topped up, drive mostly on the highway and your oil remains clean when the next oil change is due.

For average urban/suburban driving conditions, we recommend changing oil every 5,000 miles or 8,000 kilometers or every 4 months or earlier if so recommended by the manufacturer. One way to tell if your car needs an oil change is to check the oil level and condition on the dipstick. Check out this post with photos: How to check the oil level and how to read the oil on the dipstick. You can find the exact recommended intervals for your car in the Maintenance Schedule that is posted in the vehicle's owner's manual or in the Warranty and Maintenance brochure.
Why does engine oil need to be changed? The engine has many moving and rotating parts. Modern cars have smaller fuel-efficient engines that run hotter and have more complex components such as variable valve timing, valve lift, turbochargers and high pressure fuel pumps.
4-cylinder engine insideExamples of engine parts lubricated by oil in a modern 4-cylinder engine.
All of these parts are not only lubricated and cooled by oil, but require proper oil pressure to work. Any modern engine will not last for more than a few minutes without oil. An average 4-cylinder engine is filled with 4.2-4.5 quarts (4.0-4.2 liters) of oil; larger engines take in more. An oil pump circulates the oil through the oil filter and the engine lubrication system.

As you drive, some amount of oil is normally consumed and the remaining oil deteriorates and becomes contaminated with products of wear. For this reason, the engine oil and oil filter need to be changed in regular mileage or time intervals. Many engine problems are caused by lack of oil changes.

What is an oil life monitoring system? Many modern cars have an oil life monitoring system that will display a message when the oil change is due.
Low oil level on the dipstick When the oil level is low, the engine wears faster.
However, in most cars, the oil life monitoring system does not measure if the oil is dirty or if the oil level is low. It only monitors the mileage and time since your last oil change, taking into account your driving style. This means that the oil life monitor needs to be reset at every oil change to work properly. The reality is that we have seen many cases where the oil life monitor was not reset for one reason or another causing confusion and unnecessary service visits.

Considering that many modern engines are known to consume oil, it's also important to check the oil level regularly. Try googling 'excessive engine oil consumption' and you will find hundreds of complaints. As the oil level drops, the engine wears faster. Many timing chain failures, for example, are caused by running the engine low on oil. In most cars, there is no warning light for low oil level; it must be checked manually, with a dipstick.

Does synthetic oil last longer than conventional oil? Synthetic oil does last longer and can better withstand extreme temperatures, but moving or rotating engine parts still wear.
Engine oil level is full, oil is clean The oil level should be close to the "Full" mark, like in this photo.
Metal dust and by-products of oxidation mix with engine oil. Does dirty oil have the same lubricating quality as fresh new clean oil? Of course not. The synthetic oil is better for extra loads and for turbocharged engines, but it still must be changed in regular intervals. Many modern cars require synthetic oil.

Should you change your oil in the recommended time interval if the mileage is very low? Car manufacturers recommend having the oil changes done every 4-6 months or by mileage, whichever comes first. This is based on average driving of 15,000 miles per year. If you only drive for 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 warranty coverage if you still do your oil changes within the recommended mileage. However, if you want to be sure, consult your dealer.

How much does an oil change cost? Oil change prices for an average car range from $39-$59 for conventional oil to $69-$99 for synthetic or semi-synthetic oil. Premium oil brands are more expensive. A typical oil change includes an oil and filter change, fluid top up and a multi-point inspection. Always check the service menu to find out what exactly is included: Some drive-through shops offer only a quick visual inspection under the hood, while other shops lift a vehicle on the hoist and check chassis, suspension and brake components more thoroughly. To keep your car safe, an oil change with a thorough inspection on the hoist is always preferred. Dealers' oil change prices are often not much different from what small repair shops charge.