What happens when you change your oil

Changing your oil means draining the old, dirty oil from your engine, replacing the oil filter, and pouring in fresh oil. The old oil has picked up dirt, metal particles, and moisture over months of running your engine. Fresh oil protects your engine parts from wearing out too quickly and keeps everything running cooler and smoother.

You can do this work yourself in a driveway or garage, or you can pay a shop to do it. Doing it yourself costs less — usually $20 to $50 for the oil and filter — but takes about 30 to 45 minutes once you know the steps. A shop charges $30 to $75 depending on the oil type and your car.

Key Takeaways

  • You need your owner's manual to find the drain plug location, the correct oil type, and how much oil your engine holds.
  • The basic steps are: warm the engine, drain old oil into a pan, replace the filter, add new oil, and check the level with the dipstick.
  • You must dispose of old oil at a recycling center, auto parts store, or shop — never pour it down a drain or into the ground.
  • Most cars need an oil change every 5,000 to 7,500 miles, though some newer cars go 10,000 miles; check your manual for your car's schedule.

Tools and supplies you need to gather first

Before you start, collect everything in one place so you do not have to hunt for it mid-job. You need an oil drain pan (a shallow metal or plastic tray to catch the old oil), a wrench or socket that fits your drain plug, an oil filter wrench (a rubber or metal band that grips the filter), fresh oil in the type and amount your manual specifies, and a new oil filter that matches your car's make and model.

You will also want ramps or jack stands to safely lift the car so you can reach the drain plug underneath, old rags or paper towels, a funnel to pour oil without spilling, and a way to check your oil level — either the dipstick that came with your car or a rag to wipe it clean. If you do not own a drain pan or filter wrench, auto parts stores rent them for $5 to $10, which you get back when you return them.

Finding the drain plug and filter on your car

Open your owner's manual and look for the maintenance section. It will show you where the drain plug and oil filter sit on your specific engine. The drain plug is usually a bolt on the lowest part of the oil pan underneath the engine; the filter is a cylindrical canister bolted to the side of the engine, often near the top.

If you cannot find your manual, search online for "[your car year, make, model] oil drain plug location" and you will find diagrams and videos. Do not guess — the wrong bolt can damage your engine. Once you know where both parts are, you are ready to start the actual work.

The step-by-step process for draining and replacing

Start by running your engine for two or three minutes so the oil warms up and flows more easily. Turn off the engine and wait five minutes — warm oil drains faster, but hot oil can burn you. Lift the car safely using ramps or jack stands, never relying on a jack alone.

Slide the drain pan under the drain plug. Using your wrench, turn the plug counterclockwise until it comes loose, then unscrew it by hand and set it aside. Let the old oil drain completely into the pan — this takes five to ten minutes. While it drains, locate the oil filter and position the drain pan underneath it. Turn the filter counterclockwise by hand (the wrench helps if it is stuck) until it comes free, then carefully tip it so the remaining oil drains into the pan.

Wipe the filter mounting surface clean with a rag. Take your new filter, dip the rubber gasket (the ring on top) lightly in fresh oil, and screw it on by hand until the gasket touches the engine, then turn it another three-quarter turn. Do not use the wrench — hand-tight is correct. Screw the drain plug back in and tighten it firmly but not with all your strength; over-tightening strips the threads.

Adding new oil and checking the level

Lower the car back to the ground. Place the funnel in the oil filler cap opening on top of the engine and pour in the amount of oil your manual specifies — usually between 4 and 6 quarts. Pour slowly so it does not splash out. Replace the oil filler cap.

Wait two minutes for the oil to settle, then pull out the dipstick, wipe it clean on a rag, reinsert it fully, and pull it out again. The oil should reach the "full" mark on the stick. If it is low, add a little more oil and check again. If you overfill, you must drain some out — too much oil damages the engine just as much as too little. Once the level is correct, you are done with the mechanical work.

Disposing of old oil safely

Old oil cannot go in the trash, down the drain, or into the ground. It is toxic to soil and water. Most auto parts stores that sell oil — Advance Auto Parts, AutoZone, O'Reilly, NAPA — will take your old oil for free if you bring it in a sealed container. Many cities also have hazardous waste collection days where you can drop it off at no cost. Call your city's public works department or search "[your city] hazardous waste disposal" to find the nearest location.

If you took your car to a shop for the oil change, they handle disposal as part of the service. If you did the work yourself, plan to drop the old oil off within a week or two — do not let it sit in your garage for months.

Knowing when your next oil change is due

Check your owner's manual for the oil change interval — the number of miles or months between changes. Older cars and cars using conventional oil typically need a change every 3,000 to 5,000 miles or every three months. Cars using synthetic oil often go 7,500 to 10,000 miles or longer between changes. Some newer cars have electronic reminders that tell you when service is due.

Keep a straightforward record: write the date and mileage on a piece of paper and tape it inside your fuel door, or use your phone's notes app. This prevents you from forgetting and accidentally going too long without an oil change, which causes engine wear and can lead to expensive repairs.

Frequently Asked Questions

What if I spill oil on my driveway?

Soak it up when ready with rags, kitty litter, or oil absorbent powder (sold at auto parts stores). Do not hose it into the street — that is illegal in most places. Once absorbed, seal it in a bag and throw it in the trash. For large spills, contact your city's environmental department for cleanup guidance.

Can I change my oil if the engine is cold?

Yes, but it takes longer because cold oil flows slowly. Warming the engine for a few minutes makes the job faster and easier. Never work on a hot engine — wait at least five minutes after turning it off so you do not burn yourself on hot metal.

What if the oil filter is stuck and I cannot unscrew it?

Tap the filter wrench gently with a hammer to get a better grip, or wrap a rubber band around the filter to increase friction. If it still will not budge, spray penetrating oil (like WD-40) around the base and wait 15 minutes. A stuck filter usually means it was over-tightened last time — hand-tight is all that is needed.

Do I need to reset anything after changing the oil?

Some cars have an oil change reminder light on the dashboard. Your manual will tell you how to reset it — usually by holding a button on the dashboard or turning the key to a specific position. If you cannot find the instructions, an auto parts store can reset it for you in a few minutes.

Is synthetic oil worth the extra cost?

Synthetic oil costs more per quart but lasts longer between changes, so you change oil less often. If your car manual allows synthetic, the total cost over a year is often similar to conventional oil. If your manual requires synthetic, you must use it — using conventional oil voids your warranty.