SOHC EJ25: Valve stem seals?

[duncanmcrae]

My (Oz-built) '99 outback (US Legacy/liberty) is smoking like a
chimney. Engine is SOHC (phase-2?)

It seems to be valve stem related.
1) Compression is good and matched,
2) There is no oil in water or water in oil.
3) mechanic says no obvious sign of any one plug fouled.. all look the
same (which puzzles me a little)

Smoking (blue, oil smelling) is upon first acceleration after periods
of compression braking or idling. Car has done about 120k kms; service
history is somewhat unknown (we purchased approx 12 months ago.. the
smoking problem has been slowly increasing since then).

My questions are:
- Are valve stem seals a known failure mode on the ej25? I haven't
found any other references to this problem... it is possible the car
spent much of its life idle, as the mileage was low for the age (10k/
year)
- Is it possible I've dropped an exhaust valve guide, given 3)
above? Wouldn't this give me marginal compression on one cylinder?
Can this be checked by dropping the exhaust manifolds?

Mechanic wants AU$3k to pull the motor and rebuild the heads (plus $$
if he finds more to do, no doubt) . so I'm looking for a somewhat less
costly option.. (other than pumping it full of stop-smoke, 60-weight
oil and trading it in at the nearest car dealer, which is what I
suspect happened when we bought it)

Given a stem-seal diagnosis:
- Can I change the stem seals without removing the engine? I know
this is possible in general (compressed air, rope in cylinders etc),
but wonder about accessibility on the boxer. I know this will involve
removing timing belt, cams etc. I did the timing belt myself not too
long ago (100k) and it wasn't a big hassle.
- If I can't change seals in-car, can I remove the heads without
pulling the engine? I'll send the heads off to a shop to do.

any thoughts appreciated.

duncan

 

[Todd H.]

Mechanic wants AU$3k to pull the motor and rebuild the heads

For what it's worth, an independent here charged me just $1800 to
rebuild both heads in my 2.5L H-4.

But that was after I'd spent $2200 in mostly preventive crap with him,
and he flat rated some of the work because of the volume discount you
could say.

Wish I could help more, but I thought I'd throw that datapoint out at
ya.

 

[houndman]

My (Oz-built) '99 outback (US Legacy/liberty) is smoking like a
chimney. Engine is SOHC (phase-2?)

It seems to be valve stem related.
1) Compression is good and matched,
2) There is no oil in water or water in oil.
3) mechanic says no obvious sign of any one plug fouled.. all look the
same (which puzzles me a little)

Smoking (blue, oil smelling) is upon first acceleration after periods
of compression braking or idling. Car has done about 120k kms; service
history is somewhat unknown (we purchased approx 12 months ago.. the
smoking problem has been slowly increasing since then).

My questions are:
- Are valve stem seals a known failure mode on the ej25? I haven't
found any other references to this problem... it is possible the car
spent much of its life idle, as the mileage was low for the age (10k/
year)
- Is it possible I've dropped an exhaust valve guide, given 3)
above? Wouldn't this give me marginal compression on one cylinder?
Can this be checked by dropping the exhaust manifolds?

Mechanic wants AU$3k to pull the motor and rebuild the heads (plus $$
if he finds more to do, no doubt) . so I'm looking for a somewhat less
costly option.. (other than pumping it full of stop-smoke, 60-weight
oil and trading it in at the nearest car dealer, which is what I
suspect happened when we bought it)

Given a stem-seal diagnosis:
- Can I change the stem seals without removing the engine? I know
this is possible in general (compressed air, rope in cylinders etc),
but wonder about accessibility on the boxer. I know this will involve
removing timing belt, cams etc. I did the timing belt myself not too
long ago (100k) and it wasn't a big hassle.
- If I can't change seals in-car, can I remove the heads without
pulling the engine? I'll send the heads off to a shop to do.

any thoughts appreciated.

duncan

I only think valve seals when there is blue smoke when first starting
after the car has sat for a while. Not that familiar with the Boxer
motor, and how oil drains back to the pan.

Oil burning while the motor is running, I think first that the rings
might be stuck in the gruves, on an older motor. I think when a motor
starts to wear, the PCV valve recycles and burns the oil vapors (blow
by), and once it starts, and if it makes the rings stick, it will just
get worse and worse. I got a motor that was burning a qt every 30
miles on the highway, up to 550mi/qt. Thinking the rings might be
gummed and stuck. I poured a little crancase flush down the carb,
pulled the coil wire, cranked the motor, to try to suck it into the
cyls, and not burn it off. Let it sit overnite, and drove it the next
day. Gradually consumption would go down, till it maxed at 550mi/, and
I would stop treating it. Then it would start dropping off. One
mechanic said ALL I was doing was getting Oil in the rings, and
forming a temp seal..... I would Think I had a Ton of oil getting to
the rings from the burning. Another said he used to pull the plugs,
and squirt GM Top Oil in each cyl, and never thought of pouring it
down the carb..

I was buying the flush at Sears, and when the labels on the can
changed, it stopped working. I Think the label change may have meant a
different supplier was suppling it, and a different mix of solvents,
that didn't work. The car was old to start with, and I got another yr
out of it, and got another car, so didn't worry about it.

Don't know how you would get the solvent in if you have FI, but there
should be a way, or pull the plugs and squirt it in, but that would be
a chore.

Ran into a guy I know last week outside Pep Boys, and he was adding
a few qts of oil to a work truck. I started to tell him what to try,
and he said a mechanic at a shop that had a few antique cars did
something similar, that lasted a while.

VF

 

[AS]

From what you say, it seems to be valve seals related, because it is
there only when there is good manifold vacuum. Being a horizontal,
there is no reason for the problem to be present when first starting the
engine.

Did you check the PCV function?

You could end up replacing the piston rings too.

Good luck!

 

[Clifford Heath]

Mechanic wants AU$3k to pull the motor and rebuild the heads

After we had a similar job done (in Bright, Victoria) to fix
the DOHC head gasket in our Liberty, I was told by our new
mechanic here in Melbourne that there's no need to pull the
engine to do the heads. Just another data point for you, no
idea whether it's true.

 

[duncanmcrae]

From what you say, it seems to be valve seals related, because it is
there only when there is good manifold vacuum. Being a horizontal,
there is no reason for the problem to be present when first starting the
engine.

Did you check the PCV function?

Yes,, I forgot to add that. Both mechanic and I checked the PCV
independently

You could end up replacing the piston rings too.

I don't suspect piston rings, given the behaviour..

If it comes to that, I'm offloading the car or swapping the engine.

duncan

 

[houndman]

Yes,, I forgot to add that. Both mechanic and I checked the PCV
independently


I don't suspect piston rings, given the behaviour..

If it comes to that, I'm offloading the car or swapping the engine.

duncan

I believe there are compression rings, and oil scraping rings.

VF

 

[alf]

also FWIW: Subaru dealership service in Naperville, IL quoted both head
gaskets replacement for $1400-1500.

A.

 

[duncanmcrae]

I believe there are compression rings, and oil scraping rings.

yes.. and I understand that
a) compression rings are ok (given the compression test)
b) rings, any rings, require major surgery.

 

[houndman]

yes.. and I understand that
a) compression rings are ok (given the compression test)
b) rings, any rings, require major surgery.- Hide quoted text -

- Show quoted text -

what is the oil consumption?

 

[duncanmcrae]

On 20 Sep, 01:31, (e-mail address removed) wrote:
what is the oil consumption?

I think its about 1l/1000k.. haven't actually quantified it, but I
need to top up (250-500ml) every couple of weeks.

 

[Kim W]

My 99 Outback, also Australian, at 205000 km is running like new. Unless
there has been some trauma with the engine I would not suspect piston rings
or valve stem seals.
I would look for other causes.
Kim W

 

[Al]

My 99 Outback, also Australian, at 205000 km is running like new. Unless
there has been some trauma with the engine I would not suspect piston rings
or valve stem seals.
I would look for other causes.
Kim W

My '66 Corvair had leaking valve stem seals.It was a horizontally opposed,
air cooled 6 cyl. engine. The smoke was the worst when going down hill
with no gas applied. The oil would pull into the cylinders past the seals.
The seals were a rubber type that could not handle the temperatures. The
problem was fixed by replacing the rubber seals with nitril seals. This
became noticeable after about 60,000 miles.

Al

 

[houndman]

My 99 Outback, also Australian, at 205000 km is running like new. Unless
there has been some trauma with the engine I would not suspect piston rings
or valve stem seals.
I would look for other causes.
Kim W

what other causes could there be?

VF

 

[duncanmcrae]

My 99 Outback, also Australian, at 205000 km is running like new. Unless
there has been some trauma with the engine I would not suspect piston rings
or valve stem seals.

Neither would I.. but I think we've pretty much ruled out everything
except valve stem seals.

My only thoughts on why they may have gone bad:
- previous owner had car sitting for a long time and they dried out
(no pool of oil sitting on top of them like in an upright engine
design).
- I've dropped a valve guide (ie: random failure)

I would look for other causes.

I have.. any suggestions other than PCV valve?

 

[duncanmcrae]

Given a stem-seal diagnosis:
- Can I change the stem seals without removing the engine? I know
this is possible in general (compressed air, rope in cylinders etc),
but wonder about accessibility on the boxer. I know this will involve
removing timing belt, cams etc. I did the timing belt myself not too
long ago (100k) and it wasn't a big hassle.

(talking to himself..)

I've had a poke around a few service manuals, and it seems I should be
able to change the seals without getting anywhere near the timing
belt.. if the cam assembly looks anything like this

http://i113.photobucket.com/albums/n229/dennis_8047/Subaru Motor/Drivers_valvetrain.jpg

Frmo the looks of this, I should be able to:

- remove cam covers
- remove rocker assemblies
- operate on valves.
- 'installation is a reversal of the removal procedure'

Anyone know if this is the case?? If so, the job is fairly
straightforward.

duncan

 

[Kim W]

Since you don't know the history of the car I suspect that its had a hard
life and possibly poor or no service. My experience with older Subarus (EA
81) suggests that valve stem seals can contribute to smoke on start-up and
on down hill coasting - but not enough to cause significant oil consumption.
Replacing the seals in situ would be a very challenging job!
Bye
Kim W