Cont O-300D oil leak problem

I don't know what to do about this . . . hoping the collective wisdom
here might have some ideas. For the last 3 months or so, after every
flight, there are small streaks of oil on the inside of the lower
cowling on my 67 'Hawk . . . if I don't wipe them up, they drip down on
the tire of my nose gear. My mechanics have replaced all 6 rocker box
covers and gaskets, and re-flared the push rod tubes. I have spent
almost $1000.00 so far and it's still leaking. It holds pressure just
fine . . . my mechanics are now suggesting replacing all the push rod
tubes, but I get the feeling they are just guessing.
Any ideas?

www.Rosspilot.com

wrote:
I don't know what to do about this . . . hoping the collective wisdom
here might have some ideas. For the last 3 months or so, after every
flight, there are small streaks of oil on the inside of the lower
cowling on my 67 'Hawk . . . if I don't wipe them up, they drip down on
the tire of my nose gear. My mechanics have replaced all 6 rocker box
covers and gaskets, and re-flared the push rod tubes. I have spent
almost $1000.00 so far and it's still leaking. It holds pressure just
fine . . . my mechanics are now suggesting replacing all the push rod
tubes, but I get the feeling they are just guessing.
Any ideas?

There are some replacement spring loaded tubes that do a better job.
I'll have to dig up the info on them...

What gaskets did they use on the rocker covers? We had the good silicone
ones, but they needed to be replaced from over tightening, replaced the
covers as you did as well. Make sure the dipstick isn't leaking and how
much oil are you carrying? Its best kept under or at 7 quarts, if you're
keeping it topped off, that can make for a dirty cowling...

http://www.napanet.net/~arbeau/swift/cyl.htm
http://www.napanet.net/~arbeau/swift/o3006.htm

What gaskets did they use on the rocker covers?

We replaced with the orange silicone gaskets, and torqued them to
specs.

Make sure the dipstick isn't leaking and how
much oil are you carrying?

Its definitely not the dipstick, and I carry between 6-7 qts. Last
Aug, during annual, I installed an Airwolf Separator . . . because I
was blowing out all but 6 and I wanted to maintain at least 7. That
definitely isn't the problem, either (according to mechanics). Thanks
for input.


www.Rosspilot.com

On 30 Nov 2005 17:07:17 -0800, "
wrote:

I don't know what to do about this . . . hoping the collective wisdom
here might have some ideas. For the last 3 months or so, after every
flight, there are small streaks of oil on the inside of the lower
cowling on my 67 'Hawk . . . if I don't wipe them up, they drip down on
the tire of my nose gear. My mechanics have replaced all 6 rocker box
covers and gaskets, and re-flared the push rod tubes. I have spent
almost $1000.00 so far and it's still leaking. It holds pressure just
fine . . . my mechanics are now suggesting replacing all the push rod
tubes, but I get the feeling they are just guessing.
Any ideas?

www.Rosspilot.com

Give the engine a real good cleaning then run it up shut down pull
the cowl and check with an ultraviolet light to spot the source of the
oil

Give the engine a real good cleaning then run it up shut down pull
the cowl and check with an ultraviolet light to spot the source of the
oil

OK--will try the UV light . . . we didn't use that. They just used a
flashlight for visual inspection and fingers to feel for the wet spots
.. . .


www.Rosspilot.com

I don't know what to do about this . . . hoping the collective wisdom
here might have some ideas. For the last 3 months or so, after every
flight, there are small streaks of oil on the inside of the lower


Has a similar problem when the oil leak seem impossible to find or fix.
It turned out that the crankcase vent tube had been repositioned so that it
pressurized the crankcase in flight.

Once moved---no more leak.

Small streaks? SMALL STREAKS??? Man, you got one of the tight engines.
Most O300s drip more than they burn. The only reason Continental never got
into the computer business is that they couldn't figure out how to make the
computers leak oil.

I had a '64 for the better part of 15 years and never COULD completely
tighten that sucker up, even after I did a down-to-the-ground overhaul on
it.

Jim


wrote in message
oups.com...
I don't know what to do about this . . . hoping the collective wisdom
here might have some ideas. For the last 3 months or so, after every
flight, there are small streaks of oil on the inside of the lower
cowling on my 67 'Hawk

wrote:
I don't know what to do about this . . . hoping the collective wisdom
here might have some ideas. For the last 3 months or so, after every
flight, there are small streaks of oil on the inside of the lower
cowling on my 67 'Hawk . . . if I don't wipe them up, they drip down on
the tire of my nose gear. My mechanics have replaced all 6 rocker box
covers and gaskets, and re-flared the push rod tubes. I have spent
almost $1000.00 so far and it's still leaking. It holds pressure just
fine . . . my mechanics are now suggesting replacing all the push rod
tubes, but I get the feeling they are just guessing.
Any ideas?

www.Rosspilot.com

After our overhaul and complete cylinder replacement we had a tiny dent
in one of the crush gaskets on the screw-on oil filter adapter that
produced a small leak. Replaced the gasket and have had a squeaky clean
O-300D since. Knock on wood!

. my mechanics are now suggesting replacing all the push rod
tubes, but I get the feeling they are just guessing.
Any ideas?

crack in the crankcase, leaking at the through-bolts are options.

Kobra

At my most recent annual a few weeks ago, we tightened up the through bolts.

BIG diff in the quantity of oil drips.

Still have 'em, but drastically reduced.


"Kobra" wrote in message
...
. my mechanics are now suggesting replacing all the push rod
tubes, but I get the feeling they are just guessing.
Any ideas?

crack in the crankcase, leaking at the through-bolts are options.

Kobra