This Instructable is a simple step-by-step on how to change the engine oil in your car. For this example I used a 2003 Buick Park Avenue Ultra however the process is basically identical on most vehicles.

Step 1: Safety First!

Do not attempt any repairs or maintenance to a vehicle if it is beyond your knowledge level. There is no reason to attempt a repair without the actual know-how to carry it through. Most likely you will fail and it could end up costing more than just hiring a professional to make the repair for you in the first place. Remember not to attempt any repairs on a system in your vehicle if you don't have direct and full knowledge of the workings of said system. Although changing the oil in your engine is relatively simple, one mistake could result in the total destruction of your engine and at the least thousands of dollars in repairs. More importantly, a problem with your vehicle could also effect the safety of other drivers on the road.

Besides the complexity of maintenance and repairs for your vehicle there is also a certain amount of physical capability required. Particularly in this case you will be required to crawl under the vehicle and possibly lay in an awkward position while working. There is also an extensive amount of twisting and pulling required to remove the filter and oil cap. If these motions are out of the normal of your normal range, or if you have a back or shoulder issue seek the help of a competent professional. Once again it is better to hire someone to make the repair for you than it is to injure yourself in the process.

Last of all, do not attempt any repairs on a vehicle if your vision, decision making or physical abilities are impaired. This is the most dangerous thing you can do. You should never work on a vehicle while consuming alcohol or even hours after consumption. Fatigue, illness or even medications could also impair your judgement and ability to work safely. Safety is paramount, and if any of these elements are present when maintenance is necessary you should seek out the services of a trained professional. Do not attempt any maintenance under these conditions!!

Step 2: Acquire Your Tools

Requirements:

-Hydraulic jack or lift*
-Jack stand
-New engine oil
-New engine oil filter
-Adjustable wrench**
-Oil pan

Usually between $20 and $40***
Anywhere from 20 to 40 minutes

*Most vehicles have a jack included with the spare tire kit. This is usually in the trunk of the car under the mat in the center. It is also recommended to use a jack stand in case the hydraulic jack suddenly loses pressure.
**It is possible to use a pliers or vise-grips but an adjustable crescent wrench is the easiest and safest to use.
***The price of oil varies widely depending on whether you use synthetic or conventional oil. Synthetic oil has greater longevity and can handle higher temperatures, but can cost up to twice as much as conventional. The type and weight of oil will be shown in the manual and possibly on the oil cap. The price of the oil filter also ranges from as little as $5 for a cheap one to over $15 for a nice one.

Step 3: Preparation

Park your vehicle on level ground and turn it off. Its a good idea to warm the engine so the oil is warmer and drains better. However do not work on it immediately after operating it for any length of time! The oil pan and engine will be very hot! Apply the parking break to lock your rear tires because you do not want your vehicle to move while you are working under it.

Step 4: Jack the Car Up

With the car parked on level ground and the parking break engaged the vehicle shouldn't move, so now find a good jacking point on the frame. These are normally shown on the frame if you look close enough near to the wheel wells. For a front-mounted engine the oil pan and filter will be near the front of the car so place the jack behind one of the front wheels as shown here. If you can't find the designated areas by looking at the frame, refer to your owner's manual for more information. After placing it in the correct position, jack it up and place the jack stand if using a hydraulic jack.

Step 5: Finding the Drain Plug

Now locate the drain plug on the bottom of the oil pan. It is normally towards the back of the engine. Now carefully place the oil pan to catch the old oil as it drains. Remember it will come out at an angle, so position the pan accordingly. If you are working on your driveway or inside your garage you may want to place a tarp or old newspapers in the area to absorb any oil that misses the pan.

Step 6: Draining the Oil

After carefully placing the pan and any old newspapers or other barriers to protect against oil stains, you take out the plug. Do this by loosening it in the counter-clockwise direction using the adjustable wrench or the correct sized socket or wrench. If the bolt is tight, which it shouldn't be then use an extension on your wrench to increase your leverage. If this arrangement is required then the bolt was too tight. Be careful not to drop the plug into the oil as it is a messy job to find it in the old oil.

Step 7: Draining the Oil - Cont.

Now locate the filter assembly. This can sometimes be difficult because filters are not put in a standard position. They can be located on the front, back or sides of engines. Look for something similar to the filter you purchased. Once you have located it, remove it from the engine. This can be very difficult, partially because your hands may be oily and slip off of the filter. Its a good idea to wrap an old rag around it to help with your grip. Once you have a good grip slowly and steadily twist if until it begins to spin off. There will be more oil in the filter so carefully place it on the pan covering so it can drain into the pan.

When removing the oil filter, make sure that the rubber gasket ring comes off with the filter. This will need to be replaced by the new gasket that comes attached to the new filter. If the old gasket isn't removed the new filter won't seal properly and oil will leak out.

Step 8: Replace the Drain Plug

Replace the drain plug back into the oil pan now after letting it drain for around 15 minutes. Be sure to start the threading with your fingers, not a wrench. If you cross-thread it you will ruin the plug and maybe the threads in the oil pan. Twist it until it is snug but not super tight.

Step 9: Replace the Filter

Now you will replace the oil filter with the new one you purchased. Before threading it back on, its a good idea to spread some of the new oil around on the gasket ring. This will help it to seal properly and not leak. Now carefully thread it on and twist it until the gasket touches. It should say on the filter how much to tighten it after this point. Usually it is about 1/2 turn after the gasket touches, but it could be slightly more or less. Do not leave it too loose as it could vibrate off, causing catastrophic damage to your engine when the oil drains.

Step 10: Add New Oil

Now after replacing the drain plug and filter you are ready to add the new oil to the engine. The amount needed is listed in the owner's manual, probably under the "capacities" heading. Use the dipstick to measure as you pour the oil in, but also try to mentally calculate how much oil is left in the jug to make sure you aren't totally off. For the most accurate measurement check after the car has sat idle for several hours and has been parked on a level surface. Do not drastically overfill or under fill your car as either one of these could cause issues. The correct amount should be somewhere in the middle of the dipstick as shown here.

Step 11: Finish Up

After pouring in the correct amount of engine oil, replace the fill cap, check around for tools and close the hood. After picking everything up go start the engine and watch to be sure the oil pressure light goes off after start-up. Then leave the engine running and go check for any drips under the car. Run the engine for at least a minute while checking for leaks. If there are none, then you have successfully completed your oil change!

Be sure to make a note of the date and the amount of miles on your odometer when you changed your oil so you will have an idea of when to do it again in the future.