Toyota Repair: 1991 Celica GT Oil Leak, engine oil stop leak, dipstick tube

Question
I bought a 1991 Celica GT 2.2L Automatic 156K in August last year.
It started leaking oil 3 days after I bought it. The minor leak is
from a crack on the bottom portion of the timimg chain cover. The
larger leak is dripping from the drain hole in the bellhousing.
My mechanic say's it's from the rear main seal. Tried Lucas Engine
Oil Stop Leak last September and it didn't help. The car was garaged
for most of the winter. Only drove it a few times. This spring
the leak got worse. This car doesn't have a PCV valve and I am
wondering if there is something clogged that is causing excessive
crankcase pressure. I pulled the dipstick out and inserted a 12"
long brass tube into the dipstick tube to keep the oil from splattering
out. Started the engine and found a large volume of air was blowing
out the tube. Is this normal? Did the same thing on my 91 Lumina. No
noticble air is blowing out of its dipstick tube. The engine ran for  
20 minutes. Only a couple drops of oil leaked from the from the
cracked timing chain cover. About a cup leaked from the bellhousing
after I shut the engine off. The dipstick was out of the tube for that
20 minutes. The air pressure is not strong enough to blow the dipstick
out of the tube.

I borrowed a pair of ramps and put it up on them 6 weeks ago.
I dug down in the dirt to lower the ramps so that front bumper
would clear them. The car is sitting at about a 10 degree up angle
and is level crossways. I ran the engine for 20 minutes again, turned
it off and got a couple of drips of oil from the timing chain cover
and only a couple from the bellhousing drain hole.

It set for a month before I started the engine again. It ran another
20 minutes. After I shut it off no oil leaked from the cracked timing
chain cover and only a couple of drops again dripped from the
bellhousing. Air still blows from the dipstick tube and there is
no noticable change in the oil level.

Do You have any idea why it is barely leaking oil when the car is
sitting up on the ramps. I guess the next test is to take it off the
ramps and see how much oil leaks.


Answer
There are two obvious oil leaks, one at the rear main seal and one at the timing cover, both are an expensive repair, the concern is the excessive crankcase pressure, you may be spending money to repair an engine that is worn out anyway, excessive blowby is usually caused by worn pistons,cylinder walls or piston ring failure.