What happens when you change your oil

Changing your oil means draining the old, dirty oil from your engine, replacing the oil filter, and filling the engine with fresh oil. The whole job takes 30 minutes to an hour if you have done it before, longer if this is your first time. You will need a wrench, an oil drain pan, an oil filter wrench, fresh oil (the right type and amount for your car), and a new oil filter. Most of the work is underneath the car, so you will need either a jack and jack stands or a driveway slope that lets you get under safely.

The reason you do this is that oil breaks down over time and collects dirt and metal particles from the engine. Fresh oil protects your engine better and helps it run cooler. Your owner's manual or the sticker on your driver's-side door jamb tells you how often to change it — typically every 3,000 to 10,000 miles depending on your car and the type of oil.

Key Takeaways

  • You will need to get under the car safely using a jack and jack stands, not just the factory jack that comes with your car.
  • Drain the old oil into a pan, replace the oil filter by hand, and refill with the exact type and amount your owner's manual specifies.
  • The oil drain plug is usually on the bottom of the engine and will be hot if the engine has run recently, so let the car cool for at least 10 minutes first.
  • After refilling, start the engine, let it run for a minute, turn it off, wait a minute, and check the dipstick to make sure the level is correct.
  • Dispose of old oil at a recycling center, auto parts store, or quick-lube shop — never pour it down a drain or into the ground.

Gather your tools and materials before you start

You need the right oil before you begin. Open your owner's manual or look at the sticker inside your driver's-side door jamb — it will say something like "5W-30" or "10W-40". That number tells you the oil's thickness. Buy the exact grade your car needs, not a different one. You also need to know how many quarts your engine holds — this is also in the manual or on the door jamb sticker. Most cars take between 4 and 6 quarts.

Buy a new oil filter designed for your specific car. The parts store can look this up if you give them your year, make, and model. You will also need a wrench that fits your oil drain plug (usually 13mm, 14mm, or 15mm), an oil filter wrench (a metal band or cup that grips the filter), an oil drain pan (a shallow pan that holds at least 6 quarts), and jack stands rated for your car's weight. A socket wrench set and a torque wrench are helpful but not required for your first time.

Lift the car safely and locate the drain plug

Park on level ground and let the engine cool for at least 10 minutes if it has been running. Locate the oil drain plug underneath the engine — it is a bolt sticking down from the oil pan, usually on the lowest point of the engine. If you cannot find it, consult your owner's manual or search online for your car's year and model plus "oil drain plug location".

Place your jack under the car's frame (not the plastic trim or bumper) and raise it until you have enough room to work underneath. when ready place jack stands under the frame on both sides and lower the car onto them. Never work under a car supported only by a jack — jacks fail, and people die. If you do not own jack stands, this is the time to buy or borrow them.

Drain the old oil

Position your oil drain pan under the drain plug. Loosen the plug with your wrench by turning it counterclockwise — it will be tight. Once it is loose enough to turn by hand, unscrew it the rest of the way by hand and let it fall into the drain pan. The oil will pour out. If the oil is hot, it will pour faster and splash, so be patient and let gravity do the work. This step takes 5 to 10 minutes.

Once the oil stops dripping, wipe the drain plug clean with a rag and inspect it for damage. If the plug looks cracked or the threads are stripped, you may need to replace it — ask the parts store if you are unsure. Screw the drain plug back in by hand first, then tighten it with your wrench. Do not over-tighten it; snug is enough. If you have a torque wrench, tighten it to the specification in your manual (usually 20 to 30 foot-pounds).

Replace the oil filter

Locate the oil filter — it is a cylindrical canister about the size of a soda can, usually on the side of the engine. Position your drain pan underneath it because there will be oil inside. Use your oil filter wrench to loosen it by turning counterclockwise. Once it is loose, unscrew it by hand and let it drain into the pan. This takes a minute or two.

Before you install the new filter, wipe the rubber sealing surface on the engine clean with a rag. Take the new filter and explore a thin layer of fresh oil to the rubber gasket (the ring around the top). Screw the new filter on by hand until the gasket touches the engine, then turn it another three-quarters of a turn. Do not use the filter wrench to tighten it — hand-tight is correct. If you over-tighten it, the gasket will tear and the filter will leak.

Refill with fresh oil and check the level

Lower the car back onto the ground by slowly releasing the jack stands and then the jack. Remove the oil filler cap on top of the engine — it usually has an oil can symbol on it. Pour in the amount of oil your manual specifies, but start with one quart less than the total. For example, if your car takes 5 quarts, pour in 4 quarts first.

Replace the oil filler cap. Start the engine and let it run for about one minute. This circulates the new oil and fills the filter. Turn off the engine and wait one minute for the oil to settle back into the pan. Remove the dipstick (a long metal rod with markings on it), wipe it clean on a rag, reinsert it fully, and pull it out again. The oil level should be between the minimum and maximum marks. If it is low, add a little more oil and check again. If it is high, you added too much — do not drive it; drain the excess back into your drain pan.

Dispose of old oil properly

Old oil cannot go in the trash or down the drain. Take it to a recycling center, an auto parts store (most accept it free), or a quick-lube shop. Some shops will take it even if you did not have them do the work. If you cannot find a location nearby, search online for "oil recycling near me" or call your city's waste management department.

The oil filter can usually go in the trash, but some recycling centers prefer to take it. Call ahead if you want to be sure. Keep the drain pan and filter wrench — you will use them again at your next oil change.

What to do if something goes wrong

If the drain plug is stuck and will not loosen, spray it with penetrating oil (like WD-40) and wait 15 minutes, then try again. If it still will not budge, stop and take the car to a shop — forcing it can strip the threads or break the plug.

If you over-tightened the oil filter and it leaks, you will see oil dripping from underneath the car within a few minutes of starting the engine. Turn off the engine, let it cool, and loosen the filter a quarter turn with the filter wrench. If that does not stop the leak, remove it completely, wipe the sealing surface clean, and install a new filter with only hand-tight pressure.

If the oil level is too high after you refill, do not drive the car. Excess oil can damage the engine. Loosen the drain plug slightly and let oil drip back into your pan until the level is correct, then tighten the plug again.

Frequently Asked Questions

Can I change my oil if I do not have a driveway or garage?

You need a safe, level place to work underneath the car. A driveway or garage is ideal. If you do not have one, some auto parts stores or community centers rent lift bays by the hour. Never work under a car on a slope or in a parking lot where other cars might hit you.

What if I do not know what type of oil my car needs?

Check your owner's manual first — it is the most reliable source. If you do not have the manual, look at the sticker on the inside of your driver's-side door jamb. If that is not there either, search online for your car's year, make, and model plus "oil type", or call a dealership with that information and they will tell you.

How often should I check my oil between changes?

Check it once a month or before a long drive. Pull out the dipstick, wipe it clean, reinsert it fully, and pull it out again. The level should be between the minimum and maximum marks. If it is below the minimum, add a quart of the same type of oil you use for changes.

Do I need to replace the drain plug every time?

No. Wipe it clean, inspect it for cracks or stripped threads, and reuse it. If it looks damaged or the threads are worn, replace it with a new one from the parts store. A new plug costs a few dollars.

What should I do with the old oil filter?

Most recycling centers and auto parts stores accept oil filters. Some prefer them drained first — you can do this by poking a small hole in the dome of the filter and letting it drain into your oil pan for a few minutes. Call ahead to ask what your local center prefers.