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IO-540 Question ~ Oil Drain Plugs

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  • IO-540 Question ~ Oil Drain Plugs

    My IO-540 has oil drain plugs on the left and right, mid pan. The right drain access seems best for my setup as it has the least amount of conflict with the exhaust system. I plan to install a SAF-AIR quick drain. (

    This got me thinking… Should I be draining oil from both sides of the pan? Especially during break in? Obviously the tail will need to be raised to move settled oil from the rear of the pan.

    Has anyone ever installed 2 quick drains (left and right)? Seems like 1 side would drain the majority of the oil, and other side would burp out what's left. Does it matter?

    Or…. Maybe I should just call my “Over Thinkers Anonymous” sponsor.
    Rob Caldwell
    Davidson, North Carolina
    EAA Chapter 309
    BH Model B Quick Build Kit Serial # 11B-24B / 25B
    Build Log:
    YouTube Channel:

  • #2
    I used the left drain. It's not a big deal if you can't get every last drop of oil. The residual oil is next to nothing.

    I do have a remote filter also.

    There is a rear drain as well, on some sumps, to deal with the tailwheel situation I suppose??? I have one in my sump pan, but elected not to use it.
    Last edited by Battson; 01-12-2020, 02:07 PM.


    • #3
      I can't speak to the 540, but on our 360 whatever doesn't drain from the quick drain usually comes out when I remove the coarse screen.


      • #4
        You just renewed your “Overthinkers Anonymous” membership for another year.


        • #5
          I can understand the question. When you are hanging an engine on the front of your plane that costs as much as a lot of cars on the roads these days you want to do what you can to protect your investment. That extra quick drain is cheap insurance. That being said I'm only installing one on the right side of my 0-540. I also have a remote mount oil filter.


          • #6
            Depending on the engine(car, boat, and motorcycles) and where the drain plug is, I used to use an extra half quart of oil or so after all the oil has drained. Usually after half a quart, the drained oil runs clear. Just to get the extra contaminants out. Just anal I guess. I will probably do the same with my first airplane engine.


            • #7
              On marine inboard engines a lot of time oil drain access sucks. They also make simple fittings that replace the drain plug to keep a hose permanently attached to make it easier to change the oil. I have used them on a couple of boats.

              Those quick drain fittings look good and also have a hose nipple. I like it.


              • #8
                One quick drain to fit where it is the best access is the standard.

                If you use 2 Quick drains you also have 2 times the chance of a quick drain to leak.

                While not a huge problem they will from time to time start to leak a bit and need to have the o-rings replaced or replace the whole quick drain.

                As long as you use a oil filter and do regular oil changes a few tablespoons of residual oil will not be a problem.

                To assure you get all sediments out as much as possible it is very important to get the engine to operating temperature, to drain the oil -- after a flight is the best.

                The solvents in the oil are designed to pick up contaminations and sediments and hold it in solution in the oil at that point the filter can pick up most particles.

                If the aircraft sits unused for prolonged time it is best to change the oil prior to it siting to get rid of all contaminates and acids that accumulate during regular operation.

                Often folks dig out there aircraft in the spring and pull out the dipstick just to find perfectly clear oil like new even though it was well used in the fall --don't be fooled by that

                --while siting for long periods all contaminates will settle out in the engine and oil-pan giving you the impression of nice fresh oil

                All while the contaminants have been corroding away on your engine components all winter


                • #9
                  Since this post kinda got into oil and oil changes. I don't remember seeing much on the forum about oil additives such as Lucas products in auto engines used to help prevent dry starts where we get the most ware in our engines. I do admit I may have missed that discussion and maybe it should be it's own post. (Sorry Rob) Where this thought comes from is all my trucks have been diesels and I use Rotella 15-40.A while back they changed their formulation. I did a test with it where I put oil in a plastic bottle, shook it up and let it sit overnight. I was amazed that the sides of the bottle was almost dry. I now use an additive with each oil change. To clarify I have not tried it with the oil for aircraft engines. Just asking because we all have lots of money in our engines and we can't just pull over on the side of the road.