A few things to become familiar with:
The Owner's Manual or Service Manual:
Most cars come with an Owner's Manual, which is a small manual that is usually kept in the glove box. It has certain key pieces of information, most notably here, the service intervals, fluid capacities and required types of fluids.
In the absence of an Owner's manual, search the Internet for your make and model. There are many car specific sites that have all of this information. Also, most auto parts stores carry service manuals for cars that cost less than twenty dollars.
Most owner's manuals list out the service intervals or amount of time parts of the car should be serviced. Most manuals will recommend that the cars oil be changed every 6000-10,000 miles, which is far less often than the 3,000 recommended by your local oil change shop.
The amount of oil your engine holds will be listed under a section most likely title Fluid Capacities. This is often simply a table of the different fluid capacities in your car. The listing after "engine oil" should give the amount of oil needed to fill the engine in liters (L).
Type of fluid:
- Mineral vs. Synthetic Oil: Some cars may specify that synthetic oil must be used in the car. Make sure you request synthetic oil at the auto parts store if this is the case. Others may not specify either type--in this case, you may use mineral or synthetic oil.
- Oil Weight: Manufacturers will list the recommended oil viscosity. A common rating is 10W-30W. Make sure you use the proper type oil for the engine and the climate the oil will be used in. Manufacturers often recommend several types of oil to use under different operating temperatures.
Determine the service time necessary for an oil change:
- If it has been a while since the last oil change or the time of the last oil change is unknown, it's best to be safe and change the oil.
- The picture shows service intervals for an 05' Honda Pilot--the intervals are every 7,500miles.
Purchase the proper oil and filter for your car:
- Consult an auto parts store specialist on the type of oil (regular or synthetic) and weight of oil your owner's manual recommends.
- Get a filter for your car's make and model. Often auto parts stores have large books with tables that list the serial code of the car specific filter for each filter manufacturer. The specialist should also be able to help you choose the proper filter.
- Buy additional tools: an oil drain plug, oil drain pan, shop rags, a funnel, an oil filter wrench and a jack with jack stands will make the job much easier.
- NOTE: There are different grades of oil and oil filters. Nicer grades of oil are formulated to reduce the amount of build-up they leave behind. Different grades of filter reduce the amount of contaminant. Since engine deterioration has many factors that contribute to it, it is difficult to say what actually works better.
Providing proper access underneath the automobile:
- For most cars, it is necessary to lift the car up to gain access to the oil drain. Using jack stands and a jack, lift the car up so that the oil pan is accessible.
- CAUTION: Before you lift up a car, make sure you understand the proper technique. Never trust just a jack alone--always use jack stands.
Place cardboard boxes or newspapers making a four by four foot area around the drain plug. Place an oil drain pan under the drain plug. Stagger the center of the pan about six inches behind the drain plug--this will make sure you catch the initial flow of fluid.
Drain the oil:
- CAUTION: The engine oil can be very hot. Do not do perform the step right after the car has been driven. It's best to wait at least half an hour before handling the oil.
- NOTE: On some cars, it is necessary to remove plastic coverings to access the drain plug. Consult the owner's manual for instruction.
- To drain the oil, find the oil plug. It should be a bolt located on the bottom of the engine's oil pan. The oil pan is literally a pan that is at the bottom of the car's engine block. (The picture shows an oil pan with the plug circled.)
- Try to find a socket or wrench that fits properly on the bolt. Try to avoid adjustable wrenches as they often lead to stripped bolt heads. Remove the drain plug by loosening the bolt. Most plugs are standard right-hand thread or "righty tighty, lefty loosey", but it is possible that it is threaded the other way. Consult the manual to make sure there are no special instructions to remove the bolt.
- Keep the pan close as the last threads are unthreaded, as the oil might not drip out exactly as expected. Try to hold onto the bolt because finding a bolt in used oil is not as fun as bobbing for apples.
Remove the oil filter:
- The oil filter can be placed in any number of places on the engine block. Consult the manual to find out where. (The picture shows an oil filter, which in this case is white)
- Most cars use an enclosed filter, some cars like BMW's have a different type of filter. Be sure to consult the owner's manual for any special instructions on the non-enclosed filter type.
- Using the wrench, grip the filter tightly and loosen the filter by turning it to the left. Here again make sure that their are no special instructions on filter removal.
- Depending on how well the filter was designed oil might spill out of the filter when you remove it, so be ready for about a filters worth of oil to drain as the filter is loosened.
Replace the oil filter:
- Most oil filters have a rubber seal or o-ring to prevent leakage. (Dab your finger in new oil and apply a small amount to rubber, just a thin film is all you need. This will help the seal work properly.)
- Using your hand only, tighten the oil filter onto the engine by turning it the opposite way than the direction you used to loosen it. Most filters require a mere snugness with a hand-tightening method, so be careful not to over-tighten the filter. Look for special instructions for your specific filter. Most will recommend tightening the filter until the seal makes contact and then tightening it a fraction of a full turn further.
Replace the drain plug:
- This is a very important step, it's just no fun to watch all of the new oil spill out from under then car.
- When the oil is no longer dripping heavily from the drain bolt, it is time to replace the plug. Install the new drain plug and torque the plug to the recommend specification. Use of a torque wrench is a good idea as too little torque will lead to a drip and too much can permanently damage the oil pan.
- NOTE: Most manufacturers recommend that the drain plug be replaced during every service. While this may seem excessive, oil leaks are messy and if it leaks, there is no way to replace it without draining the oil. When in doubt about the condition of the drain plug, it's best to replace the plug.
Fill the oil:
- It is now time to take the car off the jack stands.
- With the car on the ground, find the oil fill cap. It is usually marked "OIL" or with a symbol that looks like a watering container and a drop. If you are unsure, make sure it is the correct one by consulting the owner's manual. (The pictured oil fill cap also has the recommended oil weight labeled.)
- Using a funnel here can make the job a lot less messy.
- Fill the oil about one liter less than the recommended oil capacity. Then use the next step and this one to fill the oil to the proper level. Adding more oil is much easier than removing oil.
Measure the oil level:
- Almost all automobiles employ a "dipstick". This is simply a long rod that "dips" into the oil pan to measure the level. The tops of most dipsticks are usually orange or yellow and have a plastic loop so that they may be removed easily.
- Remove the stick and wipe it down with a dry rag. Place the stick fully into its holster and remove it again. There should be oil on the stick.
- The oil should be in the middle of the operating range, which is sometimes denoted with two horizontal lines. Make sure the oil is within this range.
Re-check the oil level:
- Once the car has been run and warmed up.
- Park the car on a level surface and let it cool for 15 minutes.
- Use the dipstick as described in Step 10 to measure the level.
- Add oil if necessary.
Oil and filter disposal:
- Most auto parts stores will recycle used oil and filters for you. You just need to bring them the used containers and the filter.
- Dumping the oil is not only extremely toxic for the environment, it is illegal.
Changing your own oil could save you a good amount of money and it is just so gratifying to be able to change your own oil. I've found it best to take your time, take a few breaths when you get frustrated and ask lots of questions of different "experts".