What happens when you change your oil
Replacing engine oil means draining the old oil from your engine, replacing the oil filter, and filling the engine with fresh oil. Old oil breaks down over time and collects dirt and metal particles, so it stops protecting your engine as well as new oil does. Changing it regularly keeps your engine running smoothly and helps it last longer.
Most cars need an oil change every 3,000 to 10,000 miles, depending on your vehicle and the type of oil you use. Your owner's manual will tell you the exact interval for your car. Synthetic oil lasts longer than conventional oil, so if your manual says you can go 10,000 miles between changes, it usually means you are using synthetic.
You can do this job yourself if you have basic tools and a safe place to work, or you can take your car to a shop and have someone else do it. Both routes take about 30 minutes to an hour.
Key Takeaways
- You will need an oil drain pan, a wrench to fit your drain plug, a new oil filter, fresh oil in the correct type and amount for your car, and an oil filter wrench.
- Your owner's manual tells you the oil type, the amount to add, and how often to change it — this information is specific to your vehicle and matters.
- The drain plug is underneath your engine; you unscrew it to let old oil flow out, then replace the drain plug and tighten it by hand.
- The oil filter screws onto the engine and must be replaced each time you change oil; a new filter comes with a rubber gasket that you coat lightly with fresh oil before screwing it on.
- After adding new oil, you check the level with the dipstick or electronic gauge to make sure you added the right amount.
Gather the right materials before you start
You need five things to change your oil: an oil drain pan (a shallow container to catch the old oil), a wrench that fits your drain plug, a new oil filter, fresh oil in the correct type and amount, and an oil filter wrench. The drain plug is a bolt underneath your engine that you remove to let the oil drain out. The oil filter wrench is a tool that grips the cylindrical filter so you can unscrew it without your hands slipping.
Find out what type and weight of oil your car needs by checking your owner's manual or looking at the label under your hood. The manual will say something like "5W-30" or "0W-20" — this is the oil weight, and using the wrong one can affect how your engine runs. Buy the correct amount; most cars hold between 4 and 6 quarts, but your manual will tell you exactly.
You can buy all of these items at an auto parts store. The staff can help you find the right oil type and filter for your specific car if you give them your vehicle's year, make, and model. A drain pan costs $10 to $20, an oil filter costs $5 to $15, and oil costs $20 to $60 per quart depending on the type.
Prepare your car and locate the drain plug
Park on a level surface and let the engine cool for at least five minutes if you have been driving. Warm oil drains faster than cold oil, but hot oil can burn you. If you need to get under the car, use jack stands or ramps — never rely on a jack alone to hold the car up while you work underneath it.
Locate the drain plug by looking underneath the engine toward the front or side. It is a bolt sticking out of the oil pan, which is the large metal container at the bottom of the engine. Slide your drain pan underneath it. The old oil will be hot and dirty, so wear gloves and old clothes you do not mind staining.
Use your wrench to turn the drain plug counterclockwise until it comes loose, then unscrew it the rest of the way by hand. Let the oil drain completely into the pan — this takes 5 to 10 minutes. While you wait, you can locate the oil filter, which is a cylindrical canister screwed onto the side of the engine.
Replace the oil filter and drain plug
Use your oil filter wrench to grip the filter and turn it counterclockwise until it comes loose. Unscrew it the rest of the way by hand and set it aside. A small amount of old oil will spill out, so keep your drain pan nearby. Wipe the rubber gasket surface on the engine with a clean cloth to remove any dirt or old gasket material.
Take your new oil filter and coat the rubber gasket (the ring around the top) lightly with fresh oil from your new bottle. This helps the gasket seal properly. Screw the new filter onto the engine by hand until the gasket touches, then turn it another three-quarters of a turn. Do not use the wrench to tighten it — hand-tight is correct.
Wipe off the drain plug with a clean cloth and screw it back into the hole by hand until it is snug, then use your wrench to tighten it. Do not over-tighten; you want it firm but not stripped. If you have a torque wrench, your manual will tell you the correct tightness in foot-pounds.
Add new oil and check 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 says to add, usually starting with one quart less than the total capacity. This gives you room to check the level accurately.
Wait a minute for the oil to settle, then check the level. Most cars have either a dipstick (a long thin rod you pull out to see the oil level marked on it) or an electronic oil level gauge on the dashboard. If you have a dipstick, pull it out, wipe it clean with a cloth, reinsert it fully, then pull it out again to read the level. The oil should be between the minimum and maximum marks.
If the level is low, add a little more oil and check again. If it is too high, you have added too much — do not drive the car. Instead, use a turkey baster or small siphon to remove the excess oil until the level is correct. Screw the oil filler cap back on.
Dispose of old oil and run the engine
Old oil cannot go in the trash or down the drain — it is toxic and harms the environment. Take it to an auto parts store, a quick-lube shop, or a recycling center. Most auto parts stores will take used oil for free, and some will take the old filter too. Call ahead to confirm they accept it.
Start your engine and let it run for a minute, then turn it off and wait another minute. Check the oil level again with your dipstick or gauge. The level may have dropped slightly as the new oil circulates through the engine and fills the filter. Add a little more if needed to bring it back to the correct level.
You are done. Write down the date and mileage in your owner's manual or in your phone so you know when the next change is due. Some cars have a service reminder light that you can reset by following the steps in your manual.
When to take your car to a shop instead
If you do not have a safe place to work under your car, or if you are not comfortable doing the job yourself, a quick-lube shop or dealership can do it for you. The cost is usually $30 to $75 depending on the oil type and your location. Synthetic oil changes cost more than conventional oil changes.
Some cars have drain plugs or filters in hard-to-reach places, or they require special tools. If your manual mentions this or if you get stuck, a shop can handle it faster than you can figure it out. There is no shame in paying someone else to do a job you are unsure about — a mistake can damage your engine.
Frequently Asked Questions
What if I spill oil on the ground?
Clean it up when ready with cat litter, sand, or an absorbent mat to prevent it from running into storm drains. Once it is absorbed, sweep it into a bag and dispose of it as hazardous waste at a recycling center. Do not hose it down or let it drain away.
Can I mix different oil types together?
You should not mix synthetic and conventional oil, or use a different weight than your manual specifies. If you accidentally add the wrong type, you can still drive the car, but change the oil sooner than usual to flush out the mixture. Your manual tells you the correct type for your engine.
How tight should the drain plug be?
Hand-tight plus a quarter turn with the wrench is the standard. If you over-tighten it, you can strip the threads and cause a leak. If it is too loose, oil will drip out. Your owner's manual may give a specific torque specification if you have a torque wrench.
What does the oil change light mean?
The light tells you that your car's computer thinks an oil change is due based on mileage or time. It is a reminder, not an emergency. You can usually reset it by holding down a button on the dashboard or by following steps in your manual. Some shops reset it for you.
Do I need to change the oil filter every time I change the oil?
Yes. The filter collects dirt and metal particles just like the oil does, so it gets clogged over time. A clogged filter reduces oil flow to your engine. Replacing it every oil change is standard maintenance and costs much less than engine repair.