smoke from engine compartment - oil leak

B

Benjamin F. Zhou

95-Legacy L. AWD. 184,000 miles.

I did a complete check-up at a dealer at 155k. they replaced the engine
"rear oil seal", I dont know what that is. But starting about 10k ago, there
has been smoke and oil burn smell from the under the engine compartment. I
tried different engine gasgit sealer, no smoke etc. has no effect.

Although I see small pockets of engine oil every morning. I never need to
add oil between oil and filter change every 5k miles.

it seems subaru has really issue with engine oil seals.

Can anyone share more insight on this problem? what alternativedo I have
beside a complete overhaul of the several seals?

many thanks,
 
How close are to getting your next timing belt changed? There are
several seals known to leak in the front of the engine - but, to combine
labor costs, best to try to wait til the TB is changed then just replace
those seals along with, probably, the tensioner, water pump, etc. Of
course, the smoke COULD be from CV joint grease sp;attered on the
exhaust or something.
Take the vehicle to a car wash and degrease/wash the engine - carefully.
Then park the car over a large clean piec of cardboard and try to locate
the source of the oil leak(s). Proceed from there.

Carl
 
Benjamin F. Zhou said:
Although I see small pockets of engine oil every morning. I never need to
add oil between oil and filter change every 5k miles.

it seems subaru has really issue with engine oil seals.

Hi,

Interesting that the REAR seal was replaced--these seldom leak compared
to the incidence of front seals leaking. That's my experience across
several makes: it's not a Subie specific problem. Seals tend to dry out
and crack between 60k and 100k miles on many engines today. Blame the
higher temps the engines are running at due to emissions requirements.
Dry seals sometimes respond to "hi-mileage" oils and stop leak
additives, but once they crack, it's pretty much all over.

Carl gave you a good list of things to do in a cost effective manner. On
the CV joint boot, look at the inner right side first (the one that
lives over the front cat) since it gets more heat than the others. For
future reference, I'd suggest you have all the front seals done at each
timing belt change, too.

Best of luck,

Rick
 
many thanks for the detailed tips. the car is otherwise in excellent shape.
it delivers an average 33mpg, I can hardly believe it, although I drive
mostly highway, 70 miles everyday.

Ben
 
I had an oil seal leak on my 99 OBW. At first glance it might have been
easy to misdiagnose it as a rear seal leak, but it was actually the front
seal. The oil was leaking into the timing belt housing and seeping out of
there very slowly, leaving very little visual evidence of a leak. When
driving on the highway, this dripping oil would blow rearward and was
collecting on the exhaust pipe behind the engine's oil pan. When the hood
was opened the smoke would always come up from around the transmission area,
never from anywhere toward the front of the engine. It was also quite easy
to see the oil that had collected on the exhaust in an area which was almost
directly below the area where the rear seal is located. However, the rear
seal was fine, the problem was the front seal. Since it only takes a drop
or two of oil on the exhaust to create the smoke and smell, there was never
any indication on the dip stick of loss of oil due to a leak. I would
almost bet that you never had a problem with the rear seal.

KB
 
I believe I may have a similar problem with my 99 OBS. I am losing a bit
of oil and getting some pretty nasty smoke that looks like it's coming
from under the engine.

I also got a CEL 420 which is something like, "catalytic converter below
efficiency threshold." Could it be that the oil is dripping on the Cat &
burning and the heat from that is making the Cat hotter than it should be
or something?

I'm just short of 80k miles, so I'm about due for a timing belt anyway...

-Scott
 
The oil leak would have no effect on the catalytic. It could be the O2
sensor that is faulty, but not enough to give an O2 code, or it could be the
catalytic which is bad, although 80k is very unusual for a cat to go bad.
Ed B
 
I believe I may have a similar problem with my 99 OBS. I am losing a bit
of oil and getting some pretty nasty smoke that looks like it's coming
from under the engine.

I also got a CEL 420 which is something like, "catalytic converter below
efficiency threshold." Could it be that the oil is dripping on the Cat &
burning and the heat from that is making the Cat hotter than it should be
or something?

I'm just short of 80k miles, so I'm about due for a timing belt anyway...

-Scott

The P0420 code on a high-mileage car indicates that the catalytic
converter is worn out. Fortunately you state that you are under 80K,
so you should still be covered by the federal emissions warranty which
is 8 years/80K miles. Take it to Subaru, they should replace the cat
under this warranty.
 

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