Changing the oil in your general aviation plane should allow you to save considerable money, get it done right, and do it more often.  All of these are good reasons to do it yourself.

I have seen oil changes costing $150 or more lately.  For that cost you can buy all the tools you need to change your oil forever, the oil, filter and still get change from your $150.

These photos are from a C182.  You should read this article first and then check out the photos and some tips from a Bonanza.

What do you need to know to start?

There is some basic equipment you will need to have in order to do this will little mess and to do it right.  The list that follows has most of the items you will need.

1 ) New Oil

2) New Filter

3) A container to capture the old oil.

4) Wire cutters to remove the safety wire from the filter and maybe the  drain plug.

5) Safety Wire ($10.00 will last many many many years)

6) Safety Wire Twister ( from $5 to $75 )

7) Oil Filter Knife or Opener (Knife $5 plus elbow grease - Opener $50 and easier)

8) Oil Filter Grease (Dow Corning 4 ($14) or many use new oil)

9) Funnels, hoses, etc to catch all the oil.

10) Funnel to assist with new oil.

That just about does it.  Changing your own oil is pretty easy, but it is not necessarily simple.  The first thing to do is to look at where your filter is located on your plane.  If the opening of the filter is lower than the filter it will spill oil when removed.  You may also get some oil to back out of the engine while the filter is off.

I bought an inexpensive oil changing kit that contained the opener and a knife to cut the filter.  I purchased separately the safety wire, the wire twister, and Dow 4.  

It is also best to change your oil after a flight that has warmed up the engine and the oil.  You probably wont be draining all the oil from the oil cooler, nor the front of the crankshaft (constant speed prop) even with a hot engine.  I know you wont with a cold engine.  I changed the oil only once while cold.  I figured if I started draining on a Friday and it sat in the hangar all weekend, then on Monday it would be ready.  I also figured the oil filter would be easier to remove cleanly as all the oil certainly would have drained out by then.  I was wrong.  I got about a quart less out of the plane than I did on previous oil changes.  This is because the oil in the prop, oil cooler, and elsewhere did not drain as completely as they would have while hot.  Having seen the inside of my prop control and the front of the crankshaft, I know you never get all the oil out while changing your oil, even when hot.  The gray sludge in the prop end of the crankshaft when I replaced the engine with a factory remanufactured was disgusting (after 3000 hours it is no wonder).

I get back from my flight.  I then would then disconnect the lower right cowl flap (assuming I did not take the lower cowl off).  From the opened cowl flap I can reach up and attach a drain hose (clear) to the quick drain plug.  ( It is worth your while to install quick drains. It is much cleaner if you or your mechanic changes the oil.)  You will touch many hot things under the dark side of the engine the first time.  The quick drain is hot.  After I did this three times I got the technique down so I could do it quickly and without touching anything hot except the quick drain.  If you push the hose on, up and twist smoothly it is not too hot either.  If you take too much time, then the fingers do get hot. This second picture is a little blurry, but is does show the oil starting to flow to the bucket.  I would also open the oil fill tube to allow the oil to drain quicker. 

A few times this is all I would do at this time.  Maybe I got back from a late flight and I would start the draining process with the hot engine and then finish the job a day or two later.  Only works if you are in a hangar.

The bucket you collect the old oil into has to be big enough to hold all the oil you are taking out.  It should also be strong enough to carry to the oil dumping area.  Dispose of your oil correctly.

I then remove the top of the cowl.  This gives me access to top of the entire engine and the oil filter.

The oil filter will still be too hot to handle for long if I have been working continuously.  I use a funnel (well half a funnel) with a hose attached that I let hang into the same bucket I have the sump draining into.  You can see the funnel and the attached hose in the process of being put in place in the above photo.  This funnel will catch and then allow to drain into the bucket the oil that spills as I remove the filter and attempt to twist it through the right turns to get it upright and out from behind the engine and the engine mounts.  The funnel in position to remove the filter is seen in this photo.   You can see on this 182 that there is not much room and there is only one way for the filter to go in or out of that area.  These photos show several angles to try and get at the filter.      I practiced with the new filter after I made a terrible mess with my first oil change.  Using a clean, cool, filter to practice with made the the subsequent changes go much smoother.  I envy the plane owner with a straight shot at his oil filter.

The ease with which you remove the filter will depend on the quality of the access you have.  The first step is to cut off the safety wire from the filter.  Then use the socket wrench to loosen the filter.  I used a socket wrench with a fairly long extension, so I could work on the filter without having to ratchet.  Also a good idea in my case to us sockets and wrenches that were tight.  I dropped the socket once in the 2.5 gals of hot oil.  It stayed there until I needed it to tighten the new filter.

You will learn the hand dance of removing the filter, then turning it a quickly as possible in the direction so it stops draining.  Then the twisting to get it out of the area and into a container to keep draining.  You will want to take the filter apart and look at the paper element later.  However, not while it is still hot.

Once I got the old filter off, I would let the oil continue to drain.  There always seemed to be some back flow from the oil filter attach point.  As long as I had the funnel in the right place it worked well.  You will notice the funnel is only partially there.  I had to reconfigure the funnel to fit the area under the filter.  I could not find a funnel that would fit in tack.  So I cut away about half of one side and it worked fine.

The hard part is done.

I now remove the safety wire from the back of the engine.  There is a bolt designed to be the stationary side of the safety wire to the filter.  With the filter out of the way I can almost get the old safety wire out and the new one in.  The first few times I did this I used way more safety wire than was needed.  I had to thread the bolt and then bend it back.  With the two ends of the safety wire I then start twisting.  You may want to practice this outside of the engine compartment if you have not used your safety wire twister before.  You want to start the twisting, but you will not finish the twisting until after the new filter is installed.

I have always used Dow Corning 4 compound on the rubber seal of the new filter.  Many people just use new engine oil.  I bought a tube of the 4 compound an it lasted a long long time for me and all my hangar neighbors.

I always put the filter on by hand and start the treading by hand.  I want to make certain the filter goes on right, without any cross threading.  I then tighter the filter as tight as my fingers will allow.  I then us a torque wrench to finish.  The filter should be tightened to the correct torque value so it seats correctly, allows you to get it off the next time, and doesn't destroy the oil filter attachment.

Now that you have the filter in the place, it is time to safety wire the filter.  You want to put the safety wire in tension so as to tighter the filter.  You should not actually tighten the filter any with the safety wire, but it should not allow the filter to back off.  I allow the oil to continue to drain still from the quick drain. 

Yes I have started to put new oil in before I remembered to close and disconnect the quick drain.  Even with two quarts (out of 12 on the O470) it would only drain dark oil.  So now is the time to close the quick drain.  Remove the hoses to the bucket and MOVE the bucket.  I have not stepped into the bucket of hot oil and spilled it everywhere,  But I know a person who has had that experience.  Hot, unpleasant, messy, and you will be reminded every time you go to your hangar for a year.

Now it is time to fill the engine with clean oil.  You can check the dip stick as you fill, but you should know how much it will need.  Remember you now have an empty oil filter and depending on your oil cooler maybe a partially empty oil cooler to fill also.  You can't fill either one, but you may think you have too much oil until after you start the engine and allow it to pump the oil back to all the places you just drained it from.

Now take a look around to see that all your tools are back.  Look over the engine, mags or anything else you want while the cowling is off or open.  Take you time.  Rushing will not make the job any better, and you don't want to leave a tool in the engine compartment.  It may not damage the engine, but it gets real expensive replacing tools.

Put all the pieces of the plane back together.  You should have an organized place to put everything as you remove it in the beginning.  When I removed the cowl flap cable, I always (well after the first time looking for the clips for 30 minutes on the floor) put the bolts and clips back on the cable end so I knew where they were.  You will have similar parts with your plane.

Before you button everything up you do want to clean up any spilled oil on the engine or the firewall.  A little oil goes a long way.  The next step is to close up the plane and then start the engine.  You should have no oil pressure for a short time and then it should get to normal pretty quickly.  It will take a few moments (not minutes) to pump into the oil, cooler, and filter before it starts to show resistance and the pressure gauge starts showing normal numbers.

Then check for leaks.  You have done the work and now you have to see if you did it right.  There should be no oil leaks around any of the areas you touched.  There shouldn't be any oil leaks at all, but that may be another maintenance issue.

For the first 5 or 10 oil changes I did, I was the only passenger on the next flight.  I have always been a stickler for not wanting to have maintenance done just before a trip.  So I like to fly for 30 minutes to "make certain" the oil stays where it is supposed to.

How long should this take.  The first few took me 4 hours plus.  I had to figure out the right tools - funnels etc. by trial and error.  After getting the tools adjusted and having "my" procedure down I was changing the oil in about an hour.

I like to cut open the used oil filter to inspect the paper elements for any signs of bad things.

I used the inexpensive opener in the kit shown above forever.  It was a lot of work and I think having one of the newer cutters is much nicer.  You want to drain as much oil out of the filter as you can before you start to cut.  I have sometimes let the old filter sit overnight before cutting it open.

Once the filter is open you want to cut the paper element as closely to the metal frame as possible.  There will be one place where the filter starts.  Cut the filter away from the only center connection and then follow the edges around the filter on the top and bottom. When you are done, you will be able to pull the element away from the filter.  You want to inspect the outside of the element in between the creases and folds. You are looking for anything abnormal.  You will probably see little specks of all sorts of things.  Most of what you find will be normal.  If you can crush it with your fingers, then it is just some sludge build up.  If there are little pieces of metal or any metal bigger than a pencil point, then you want to show it to your mechanic.  Don't destroy the filter element.  You have not destroyed it by opening it.  I have on several occasions felt there was something in there I wanted a "real" mechanic to look at before I would feel at ease.  I would keep the filter folded but put it on several pieces of paper towels to absorb the oil.  You can keep your old filter elements this way for several months.

If you fly a certified airplane you are required to place an entry in the log books.  It should contain this information.

A description of work performed.

The date of completion of the work performed.

 The name of the person performing the work (either you or a certified mechanic).

Sample engine log entry is:

March 10, 2004  Tach 1755  Drained oil, removed filter.  Replaced with Champion 4810 filter and 12 quarts of Shell 15w50.  Inspected filter element for debris.  Found none.  Checked for leaks, none found.  Your Name and signature and private pilot certificate number 123454321.

I always felt a great deal of satisfaction, knowing the job was done right by the person who cared the most and I saved some money in the process.