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All knowing beeb: Identify this oil drain plug!

Discussion in 'General' started by Suburbanrancher, Jun 21, 2015.

  1. Suburbanrancher

    Suburbanrancher Chillzilla

    So I'm changing the oil on an RV onboard generator (Onan QD3200) and I come across the oil drain plug. Normally I always replace these with magnetic plugs, but as I'm servicing it I come across this:


    In all my years I've never seen a two-piece oil drain plug like this; it's a cap that unscrews, and the center is a separate piece that drops out and apparently maintains it's seal to the outer cap using an o-ring inside the cap.

    Can anybody tell me what standard this is / who makes it / is it common? Been looking all over and I can't find any info. I understand it's an extension piece for the original drain, but I'd still like to get a replacement magnetic cap for it if possible.

    Thanks in advance for any help.
  2. daveknievel

    daveknievel I love orange kool-aid

    its an AN fitting. used on aircraft. depending on the size, I might have some laying around that I robbed from an A-4 Skyhawk.

    cars use them too, for fuel line and oil lines.
  3. flyboy

    flyboy Well-Known Member

    Boom! 7 mins for the answer!
  4. Suburbanrancher

    Suburbanrancher Chillzilla

    Yup - Dave knows his stuff for sure :up:

    Now then...why - WHY - would they use this for a drain plug? There's no pressurized line, no level of aircraft safety required...ugh.

    Just seems way complicated for 'unscrew and watch fluid come out'. And I still can't find a magnetized fitting for it :(
  5. BSA43

    BSA43 Well-Known Member

    I would guess that it's to allow the oil to be drained into a container without making a howling mess.

    That would require a hose, however.

    Does the elbow swivel?
  6. daveknievel

    daveknievel I love orange kool-aid

    yep. its so you can put a hose on it to remotely drain it. I'm sure the generator is used in multiple applications and positions. measure the I.D. of the 90* fitting, or if there might be a number stamped on the cap. I will check my "box 'o junk" tomorrow.
  7. Mikey75702

    Mikey75702 Well-Known Member

    They do it because of the hole they put there for the drain... The fitting would allow the oil to drain out of the hole vs on the panel, then run out of the hole. Just a different way to do it. They make those caps in single piece as well, if the two piece cap drives you nuts.

    This should be the size you have... http://www.summitracing.com/parts/aer-fbm3602/overview/
  8. cincigp

    cincigp Well-Known Member

    Yep, standard AN stuff. Like someone else said, if you want to replace it measure the ID and round to the nearest 1/16. Then whatever number is in the top of the fraction is your AN fitting size. I doubt they make them in magnetic versions though, and actually in this application I doubt it would do much good since once the oil is filled, the oil leading up to the drain plug is probably stagnant.
  9. bitchcakes

    bitchcakes reluctant member

    Aircraft 'quick drain' plug would be the upgrade

  10. daveknievel

    daveknievel I love orange kool-aid

    What he said. :up::up:

    You will sell or trade that in before it even needs another oil change anyway.
  11. grantcarruthers

    grantcarruthers Well-Known Member

    Love that thing on my RV4. Easy to get hose fitted to that nozzle too. Doesn't do me any good as I can't reach it without removing the cowl anyway but cool feature for those that could.
  12. Suburbanrancher

    Suburbanrancher Chillzilla

    Nice. I'm going to see about losing that elbow altogether and installing one of these :up:

    Haters gonna hate.

  13. cincigp

    cincigp Well-Known Member

    If you take the elbow out and install one of those plugs you won't actually be draining all of the oil out unless the generator is tilted toward the plug. If that plug is installed horizontally, oil will remain in the sump up to the edge of the blue center part. I believe those are intended to be installed vertically.

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