Cont O-300D oil leak problem

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.


JayYou told your mechanic that you had an oil leak, and that he
should go fix
it?
Whoo-eee...I'll bet he's had visions of sugar plums dancing in his head
for
weeks! Talk about a license to steal...

Not at all. I was there every minute, observing everything. I even
flew to Danbury (Coastal Aviation) to pick up the new rocker box covers
myself. I did the runups on the ramp after each attempt to fix it.
These guys were definitely not trying to exploit me, and they are just
as frustrated as me by the persistant leak. In fact, I am forwarding
all the comments from the NG to them at their request. They want to
fix it as much as I do.

Never, ever send an A&P on a fishing expedition. You'll only get
hooked,
and everything will smell fishy...

Sound advice, but this is not the case here. Thanks . . .


www.Rosspilot.com

Never, ever send an A&P on a fishing expedition. You'll only get
hooked,
and everything will smell fishy...

Sound advice, but this is not the case here. Thanks . . .

I know you didn't, Lee. I guess I forgot the little smiley thingy...

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Small Continentals typically leak from both ends of the pushrod
tubes. The rubber couplings at the case need to be replaced, which
requires pulling the cylinders off, at which time the cylinder base
seals (o-rings) should be done, too. The head end of the tubes will
often leak until the rocker covers are removed, cleaning solvent (like
Brake and Parts Cleaner or laquer thinner) is used to flush out the
tube/head joints, and a wicking Loctite is run into them. If it's the
front crankshaft seal, there's a split version available to install
without any fuss.
The oil tank or accessory cover gaskets might be leaking, and
worst of all, the crankcase joint might be starting to seep.

Dan

If the pushrod tubes are the same as on the big bore Continentals then
the cylinders do not need to be pulled, you just need the tool to
compress the springs. And no mechanic worth the title uses loctite on
those tubes. If you get the gaskets in right they do not leak. Very
easy to tell with a little mirror.



wrote:

Small Continentals typically leak from both ends of the pushrod
tubes. The rubber couplings at the case need to be replaced, which
requires pulling the cylinders off, at which time the cylinder base
seals (o-rings) should be done, too. The head end of the tubes will
often leak until the rocker covers are removed, cleaning solvent (like
Brake and Parts Cleaner or laquer thinner) is used to flush out the
tube/head joints, and a wicking Loctite is run into them. If it's the
front crankshaft seal, there's a split version available to install
without any fuss.
The oil tank or accessory cover gaskets might be leaking, and
worst of all, the crankcase joint might be starting to seep.

Dan

If the pushrod tubes are the same as on the big bore Continentals then
the cylinders do not need to be pulled, you just need the tool to
compress the springs. And no mechanic worth the title uses loctite on
those tubes. If you get the gaskets in right they do not leak. Very
easy to tell with a little mirror.

The O-200/O-300 engines have the pushrod tube swaged into the cyl head
assembly. There is an elastomeric seal at the crankcase end only. I
understand there is a re-swaging tool that I assume you already have
used to tighten these joints, but that tool can only do so much before
it damages the tubes etc. The use of loctite is appropriate.

I thought someone had mentioned it earlier (maybe on another post?) &
I've never tried it, but perhaps you could pressurize the crankcase
thru the breather line to maybe 1-2 psi & do soap bubble tests. Don't
go any higher or you would probably blow out the front crankshaft seal.
BTW I assume the front seal has its split in the correct quadrant?

Chances are otherwise pretty good the leak is around one of the case or
pan splits, in which case a vaccum should be used to suck in a sealant
after cleaning.

wrote:
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.



JayYou told your mechanic that you had an oil leak, and that he
should go fix
it?
Whoo-eee...I'll bet he's had visions of sugar plums dancing in his head
for
weeks! Talk about a license to steal...

Not at all. I was there every minute, observing everything. I even
flew to Danbury (Coastal Aviation) to pick up the new rocker box covers
myself. I did the runups on the ramp after each attempt to fix it.
These guys were definitely not trying to exploit me, and they are just
as frustrated as me by the persistant leak. In fact, I am forwarding
all the comments from the NG to them at their request. They want to
fix it as much as I do.

Well clearly there was more work done than new gaskets and some flaring.
The new gaskets are about $8 each if you get the good silicone ones.
Takes an hour to install them, at most.