The best reason to regularly change the engine oil and filter is to prolong engine life. Contaminants in engine oil come from a variety of sources.
In a gasoline engine, the oil is contaminated primarily by combustion gases seeping past the piston rings. Minute airborne particles that escape past the air filter also contribute to oil contamination. As engine components wear, more gases will slip past the rings during the compression and power cycle.
Over the past decade, gasoline-refining technology has decreased combustion pollutants, helping to reduce engine oil contaminants. Additives increase the ability of the engine oil to maintain adequate lubrication quality even when contaminated. As technology advances, the time between oil changes is lengthened.
As a result, perhaps oil changes will be necessary only a few times during the life of the engine. Until then, timely oil changes, maintaining the engine and changing the air filter will help prolong engine life.
Changing the oil and filter sounds easy. However, several tricks can simplify the task. Performing the job in a set sequence with the proper tools will not only make it easier, it will also reduce the likelihood of making a mess, or worse, a costly mistake. If the procedure can be performed quickly and easily, it can be an incentive to do it regularly.
There are a few supplies needed for the procedure:
There are two methods of performing an oil change. The first is to normalize the engine operating temperature. That requires the engine to idle for a time or a few trips around the neighborhood. Now that the engine is warm, drain the sump and change the filter. The thought behind this is contaminates are suspended in the oil and when the sump is drained, the harmful contaminates drain with the oil.
The second method is to drain the oil when the engine is cool, when a good percentage of the oil has settled into the sump. For a couple of years, I practiced the first method. Both have merit; however, the second method works best for me.
With either method, the most important step is to develop a routine that works. The location where the procedure is performed should be reasonably level as most sump bottoms are formed to tilt toward the drain plug.
Draining the oil when the engine is cool (method number two) offers the following benefits: It is not necessary to circle the block a few times or have the engine at high idle for 20 minutes trying to warm the oil; when the engine has been at rest for several hours and the drain plug is removed, the oil is cool and drain flow is more controllable; pressure between the filter and the filter housing has bled off, making filter removal a cleaner process. A cleaner process is generally a quicker process.
Another benefit of the second method is that it is easier to detect coolant (antifreeze) leaks. When undisturbed, the water and antifreeze will settle around the drain plug. By first cracking the drain plug slightly, if there is a coolant leak, water and antifreeze will be the first to run out. Use a glass jar to catch what has discharged for inspection.
If only oil emerges, continue to run out to drain plug as the following describes. Coolant leaks may also be observed as brown bubbles above the oil level on the dipstick.
Gather the necessary supplies. Wearing disposable gloves, use a paper towel to clean the area around the oil fill cap.
Open the cap to break any minor vacuum created when the drain plug is removed. Place the drain pan slightly off-center of the drain plug.
Using a suitable wrench (preferably six- point), unscrew the drain plug to the end of the threads. Slowly tip the plug upward and away to get a feel of where to place the drain pan to catch the oil. Be sure to place the pan so when draining slows, the pan is catching the oil.
While the sump is draining, open a container of new oil and pour oil into the center of the new filter. Pressure from the pump pushes the oil through the media (from outside to inside), out the center to the oil galleries.
Note: Some people advise against the practice of prefilling the filter. The reason is that new oil is often dirtier than what is recommended for engines. When new oil is introduced into the inside of a new filter, this oil will then pass unfiltered into the engine and critical frictional surfaces (cam/follower, ring/bore, bearing/shaft, etc.).
Slowly roll the filter around; this allows the filter media to absorb the oil and minimize oil starvation at the bearings upon initial start-up.
While the filter media is wicking up the oil and the sump is draining, remove the old filter and turn it over to drain. In many cases, the friction provided by the disposable gloves will allow a sufficient grip to unscrew the old filter without using a filter wrench. A filter wrench will be required if the filter is inaccessible by hand, if the filter was over-tightened or the engine was overheated.
Clean the filter seat surface of the filter housing. Be sure the rubber gasket from the old filter is not stuck to the filter seat surface. Clean the area around the drain plug and install; wipe area again and check for drain plug weep. One suggestion here: a copper gasket on the drain plug lasts longer than a fiber washer or nylon gasket.
The angle at which the filter mounts to the engine will dictate how much oil to put in the filter. Filters mount at different angles depending on engine design. If the filter mounts vertically, then fill the filter. Many four- and six-cylinder engine filters mount at an angle. Filling the filter in these instances will cause a mess.
After a final fill-up in the center of the new filter, coat the filter seal with new oil. Install the filter according to filter torque instructions; this makes it easier to remove the filter next time. I prefer to begin filling the crankcase with the open container I used for the filter; it helps keep track of the amount. Prop the container into the crankcase fill.
While the container is draining, clean up the old filter and drain container. Use a type of drain container that seals tightly for recycle purposes.
Many refuse stations have a used oil reclamation container. In between adding the remaining specified amount to the crankcase, do a final cleanup from underneath, put the tools away and inspect the engine compartment for leaks. After filling with the recommended amount, close the fill cap and remove the disposable gloves.
Start the engine and check for leaks. This whole process can be accomplished in about 10 minutes. The goal is to develop a routine that is easy to perform and works well.