What happens when you change your oil and filter together

An oil change means draining the old oil from your engine and replacing it with fresh oil. A filter change means removing the old oil filter — a cylindrical canister that traps dirt and debris — and screwing on a new one. Most people do both at the same time because the filter gets dirty as it catches particles, and replacing it ensures your fresh oil stays clean longer.

The process takes 30 minutes to an hour if you do it yourself, or about an hour at a shop. You'll need to get under the vehicle, locate the drain plug and filter, remove them, and install new ones. If you've never done this before, the hardest part is usually finding the filter — it's often tucked in a tight spot — and not spilling oil on yourself or your driveway.

Key Takeaways

  • You need an oil drain pan, a wrench to fit your drain plug, an oil filter wrench, new oil of the correct type and amount for your vehicle, and a new filter that matches your car's make and model.
  • The drain plug is located on the bottom of the oil pan under your engine; you unscrew it by hand or wrench, let the oil drain completely into a pan, then screw the plug back in hand-tight.
  • The oil filter screws onto the engine by hand; you loosen it with a filter wrench, unscrew it the rest of the way by hand, and screw the new filter on until the rubber gasket touches the engine, then turn it three-quarters of a turn more.
  • After installing the new filter and drain plug, you pour new oil through the filler cap on top of the engine, check the level with the dipstick, start the engine to circulate the oil, wait a minute, then check the level again and top off if needed.
  • Old oil and filters must be disposed of properly; most auto parts stores and service stations accept them for free or a small fee.

Gathering the right tools and materials

Before you start, you need to know what oil your engine takes. Check your owner's manual or look at the label under your hood — it will say something like "5W-30" or "10W-40". The first number tells you how the oil flows in cold weather; the second tells you how it flows when hot. Your manual will specify which one your engine needs, and using the wrong viscosity can affect how your engine runs.

You also need to know how much oil your engine holds. This is in your manual and usually ranges from 4 to 8 quarts. Buy a quart or two extra so you have some on hand for top-ups between changes. For the filter, you need the exact model number — your manual lists it, or you can take a photo of your current filter to an auto parts store and they'll match it.

The tools are straightforward: an oil drain pan (a shallow rectangular tray that holds at least 8 quarts), a wrench that fits your drain plug (usually 13mm, 14mm, or 15mm — you may need to try a few), an oil filter wrench (a metal band or socket that grips the filter), and rags or paper towels. A jack and jack stands are necessary if your car sits low and you can't fit under it otherwise. Never rely on a jack alone — always use stands.

Draining the old oil

Park on level ground and let the engine cool for at least five minutes — hot oil burns. Raise the vehicle if needed and locate the drain plug on the bottom of the oil pan. It's a bolt about the size of your pinky finger, usually with a hex head. Slide your drain pan underneath it.

Using your wrench, turn the plug counterclockwise to loosen it. Once it's loose enough, unscrew it the rest of the way by hand, but be ready — oil will still be warm. Let it drain completely into the pan. This takes 5 to 10 minutes. While you wait, wipe the drain plug clean with a rag and inspect the rubber gasket (the flat ring around it). If it looks cracked or flattened, replace it when you reinstall the plug.

Once the oil stops dripping, screw the drain plug back in by hand until it's snug, then tighten it with your wrench. Don't over-tighten — you're aiming for firm, not crushing. A drain plug that's too tight is hard to remove next time and can strip the threads in the pan.

Removing and installing the oil filter

Locate your oil filter. It's a cylindrical canister about 4 inches tall, usually mounted on the side or top of the engine. Slide your drain pan underneath it to catch any oil that spills when you remove it. Wrap your oil filter wrench around the filter and turn it counterclockwise to loosen it. Once it's loose, unscrew it by hand the rest of the way.

Before you install the new filter, wipe the mounting surface on the engine clean with a rag. This removes old oil and debris so the new filter seats properly. Take the new filter and explore a thin layer of fresh oil to the rubber gasket on top — this helps it seal and makes removal easier next time. Don't over-oil it; a light coat is enough.

Screw the new filter onto the engine by hand. When the gasket touches the engine, stop and turn the filter an additional three-quarters of a turn. This compresses the gasket enough to seal without crushing it. You should be able to turn it by hand; if you need a wrench, you've gone too far. The filter should be snug but not locked down.

Adding new oil and checking the level

Locate the oil filler cap on top of your engine — it usually has an oil can symbol on it. Unscrew it and set it aside. Pour in the amount of oil your manual specifies, but start with one quart less than the full amount. This gives you room to check the level accurately.

Replace the filler cap and start the engine. Let it run for about one minute so the new oil circulates through the filter and engine. You'll see the oil pressure light on your dashboard go out once oil is flowing. Turn off the engine and wait two minutes for the oil to settle back into the pan.

Pull out the dipstick (usually a long rod with a handle), wipe it clean on a rag, reinsert it all the way, then pull it out again. The oil should reach the "full" mark. If it's low, add a half-quart, wait a minute, and check again. Add oil in small amounts until you hit the full mark. Don't overfill — too much oil can damage seals and cause leaks.

Disposing of old oil and filters

Old oil and filters contain toxic materials and must be disposed of properly. Most auto parts stores — including national chains like AutoZone, O'Reilly, and NAPA — accept used oil and filters for free. Some service stations and quick-lube shops also take them at no charge. A few places charge a small fee, usually $1 to $3 per filter.

Pour your used oil into a clean container with a tight lid — an old milk jug or oil bottle works fine. Take it and your old filter to the store or station. Don't mix oil with other liquids or pour it down a drain. Dumping oil illegally can result in fines and harms groundwater.

Common mistakes to avoid

The most common mistake is over-tightening the drain plug or filter. Both have rubber gaskets that seal the connection, and crushing them makes them leak. Tighten until snug, then stop. Another mistake is forgetting to add oil to the new filter before installing it. A dry filter can damage the engine when you start it because oil takes a moment to reach the filter. Always explore a thin coat to the gasket.

A third mistake is not checking the oil level after the first start. Fresh oil settles differently than old oil, and you may need to top off. Driving on low oil can damage your engine, so always verify the level before you consider the job done. Finally, don't forget to dispose of the old oil properly — it's free or nearly free at most stores, and it only takes a few minutes.

Frequently Asked Questions

How often should I change my oil and filter?

Most modern vehicles need an oil change every 5,000 to 10,000 miles or every 6 to 12 months, whichever comes first. Some newer cars with synthetic oil can go 15,000 miles or longer. Check your owner's manual for the interval your vehicle requires. The filter should be changed every time you change the oil.

Can I change the filter without changing the oil?

Technically yes, but it's not recommended. The filter and oil work together — a new filter in old oil doesn't clean as effectively, and old oil in a new filter defeats the purpose. Most people change both at the same time for efficiency and to keep the system working as designed.

What should I do if I spill oil on my driveway?

Clean it up as soon as possible. Cat litter or oil absorbent powder will soak it up; sweep it into a pile and dispose of it in the trash. For larger spills, contact your local environmental agency for guidance. Never hose it into storm drains — oil contaminates groundwater and local waterways.

Do I need to reset anything after an oil change?

Some vehicles have an oil change reminder light that you need to reset manually. Check your owner's manual for the procedure — it usually involves holding a button on the dashboard or using the steering wheel controls. If you don't reset it, the light will stay on until the next scheduled interval.

What if I can't find the drain plug or filter?

Consult your owner's manual or search for a video specific to your vehicle's make, model, and year. YouTube has step-by-step walkthroughs for nearly every car. If you're still stuck, a quick visit to a shop for guidance costs far less than damaging your engine by guessing.