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How I Lost 1.5 Quarts of Oil in 15 Minutes .
By Kyle Boatright - KBoatri144@aol.com
After landing following a short flight on Sunday, I saw a few drops of oil on
the ground under the aircraft. Once I rolled it into my hangar, took a look
at the belly, and it was COVERED in oil... I pulled the dipstick (which was
just sitting there loose, not screwed in??), and checked the oil level - down
from 6 quarts to 4.5 quarts.. I thought this wasn't good, even though there
had been no signs of a problem from the engine instruments.
Next, a buddy and I pulled the cowl, took a look, and it was obvious that all
of the oil had come out of the breather tube. I thought this was BAD. I was
thinking big $.
Several days and quite a bit of troubleshooting later (I called
textron/lycoming, did a compression check, etc), my favorite AI and I had
found nothing major wrong. The folks at Lycoming did ask how my breather was
installed, and pointed out that my breather hose exit was beveled the wrong
way - it draws a vacuum in the airstream, and should be installed to AVOID
drawing a vacuum.
When I went over this with my AI, we discussed the breather tube, and I
brought up the fact that the oil filler cap was completely loose. He said..
That's it - You had a breather tube drawing a vacuum through the engine, and
with the oil cap off, there was a path for the vacuum to pull air through
the engine, and this vacuum had sucked 1.5 quarts out in 15 minutes...
I added a quart of oil, put the filler cap on correctly, went flying, and
vola-no oil on the belly.
Lesson learned. Glad it was on a short flight, not on a cross-country.
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