I posted the info that follows on the Yahoo group about a year ago. Since then I've done lots of testing both on the street and on autoX courses and all seems well. I don't claim this as a guaranteed fix or that you can't reck something by doing this, but for the past year and close to 1000 miles its been working for me.
Two years ago, my 336 started leaking heavily from its input shaft seal. So I
pulled the transaxle, put in a new seal and it stopped leaking. For about a
month. Then it started right back up (Yes my flywheel bushing is new and also
looks to be working fine).
I was then directed to make sure my breather was clean and clear of obstruction.
I cleaned out some junk and tried the car and found it to be fine around town,
but at freeway speeds (especially higher freeway speeds) it would leak a
considerable amount (I wired the bottom of an Altoids can to the transmission to
catch the oil so I could compare results).
Knowing that my seal was new and that the oil had to defy gravity to leak out
caused me to focus on the idea that there was a force (pressure) that was
pushing the oil out. So I wondered if I could create a force to keep the oil
in. I then came up with the idea to run a vacuum line from the engine to the
breather port on the transaxle to create a low pressure area in the transaxle
which would cause the outside air pressure to persuade the oil to stay inside
the gearbox.
I didn't want to risk sucking up any oil so I got a coolant overflow tank and
put it in mid line to act as a catch tank which I could check and monitor if it
was sucking up oil. There are pictures in the album 0467R of the early fitting
(I later added a piece of cloth over the breather port between it and the
plastic tubing to act as a bit of a filter and mounted the lower tubing so it
didn't go up and down between the transaxle and the tank).
I ran the car up and down hills, pausing and letting it idle, revving its engine
etc., trying to replicate as many driving situations as possible and especially
those with the transaxle pointed down in the back (on a hill) with high vacuum
to see if it sucked up any oil. It did. A little but it seemed to maintain a
level of an ounce or two so I kept driving.
I drove it several hundred miles like this and in one of my autocross races
where it sucked up a little more oil than normal. The thing is it didn't drop
one bit of oil (once I had cleaned out the old oil that had accumulated in the
bellhousing). Not one spot in the driveway.
But after the race I decided to pull the system as it had sucked up a little
more oil and I was tired of worrying about it and I wanted to see how it did
with just its breather cap as I had shown that internal pressure had been my
problem.
Once I pulled it, it went right back to leaking prodigiously at highway speeds.
So I decided to set it back up, but this time I put a rubber cap over the inlet
to the catch tank at the top and drilled a small hole in the cap for the vacuum.
This was to act as a vacuum restriction to hopefully lessen the amount of oil
that would get sucked up.
That was about a year ago now and I'm still leak free and only once sucked up a little gear oil, which was during an autocross, and was just enough to have some oil in the clear rubber tubing, not enough to put any amount up into the catch tank.
Of note: Since my toyota motor is a JDM motor, it uses an MAP sensor instead of a mass airflow sensor in its fuel injection system. So my engine doesn't care when it gets its air from (metered or unmetered) just how much total vacuum it has. A carbureted engine also wouldn't care about the added vacuum line, but a US spec fuel injection engine would. In that case, an electric vacuum pump could be used or if you are a serious engineer, you could create a device that in the airflow under the car would generate a vacuum and use that.
Anyway, I'd be honored if this helps anyone. I have an OCD problem with a car I own leaving oil marks, and thus, this fixed has saved the Europa from me giving up on owning it.
Ben
0467R
