Clacking from head/block

[hachiroku]

I have a 1996 Outback that has not been driven for 4 years, and has not
been started for ~2. We changed the oil ast week, charged the battery and
started it up. There was a clacking noise that seemed to be coming from
the passenger's side head, or close to the block, that smoothed out
somewhat when we revved the engine but never went away, and got worse at
idle.

I think it's a sticky valve and am hoping it will free up as the car is
run more. Any ideas?

This is a 1996 Outback with the 2.2L engine.

 

[hachiroku]

I have a 1996 Outback that has not been driven for 4 years, and has not
been started for ~2. We changed the oil ast week, charged the battery and
started it up. There was a clacking noise that seemed to be coming from
the passenger's side head, or close to the block, that smoothed out
somewhat when we revved the engine but never went away, and got worse at
idle.

I think it's a sticky valve and am hoping it will free up as the car is
run more. Any ideas?

This is a 1996 Outback with the 2.2L engine.

Added rec.autos.tech...

 

[Nobody > (Revisited)]

Added rec.autos.tech...

Possible cam-belt tensioner? IIRC , it's partially an oil-pressure
hydraulic setup, would make sense with the conditions.

It's always a gamble, but I'd give it a heavy dose of one of the "thin"
(distillate type) "engine cleaner" additives. Give it a few
long/hard/hot runs to let it work 200-500 miles or so, a good excuse to
go on a mountain-pass road trip.



--
"Shit this is it, all the pieces do fit.
We're like that crazy old man jumping
out of the alleyway with a baseball bat,
saying, "Remember me motherfucker?"
Jim “Dandy” Mangrum

 

[hachiroku]

Possible cam-belt tensioner? IIRC , it's partially an oil-pressure
hydraulic setup, would make sense with the conditions.

It's always a gamble, but I'd give it a heavy dose of one of the "thin"
(distillate type) "engine cleaner" additives. Give it a few
long/hard/hot runs to let it work 200-500 miles or so, a good excuse to
go on a mountain-pass road trip.

That's what I was thinking. Trying 1/2 QT of Marvel Mystery Oil for this
change and the next one. But it's still not on the road yet, the E-Brake
is frozen and the rotors and pads are no longer separate items...

 

[clare]

That's what I was thinking. Trying 1/2 QT of Marvel Mystery Oil for this
change and the next one. But it's still not on the road yet, the E-Brake
is frozen and the rotors and pads are no longer separate items...

20 minutes running with MMO will LIKELY solve the problem if it is a
gummed up lash adjuster.

 

[hachiroku]

20 minutes running with MMO will LIKELY solve the problem if it is a
gummed up lash adjuster.

I was hoping for some back-up approval!

This is what I was thinking, too. We only ran the car for about 15 minutes
with fresh 10W30, so next time I go there I'll put in some MMO and let it
run for a while.

Perhaps after I change the valve cover gaskets...I *HOPE* that's what's
leaking! :0

(It's not dripping, but there is burning oil coming from that area when
the engine is running. Had the same thing happen on a Supra...)

 

[Nobody > (Revisited)]

Perhaps after I change the valve cover gaskets...I*HOPE* that's what's
leaking! :0

(It's not dripping, but there is burning oil coming from that area when
the engine is running. Had the same thing happen on a Supra...)

Also a possible bad head gasket, but not the usual DOHC 2.5L
chamber-to-waterjacket fail mode that is so devastating.

It's a slim chance, but possible, usually the only external leaks are
coolant. IIRC, the oil passages are a fair distance inside so the
probability is low.

I did see that on an old 230 ci Chev 6 years ago. That engine design
wasn't so wound up tight that head gasket fails were pulling the pin on
a grenade. The leak was small, nobody bothered with fixing it until it
was torn down for a ring and valve job. There was a small 4" meandering
"track" in the felt part of the gasket from an oil passage to the
outside world. My guess it was some kind of long fiber that made it's
way into the felt and got gradually eaten away.

I don't know why, but I remember odd/weird crap like this better than
more important stuff <g>

HG fails are often progressive on the DOHC 2.5L, so if the valvecover
gaskets don't fix the oil leak... get ready for doing that HG job ASAP.


--
"Shit this is it, all the pieces do fit.
We're like that crazy old man jumping
out of the alleyway with a baseball bat,
saying, "Remember me motherfucker?"
Jim “Dandy” Mangrum

 

[Dave__67]

Also a possible bad head gasket, but not the usual DOHC 2.5L
chamber-to-waterjacket fail mode that is so devastating.

It's a slim chance, but possible, usually the only external leaks are
coolant. IIRC, the oil passages are a fair distance inside so the
probability is low.

I did see that on an old 230 ci Chev 6 years ago. That engine design
wasn't so wound up tight that head gasket fails were pulling the pin on
a grenade. The leak was small, nobody bothered with fixing it until it
was torn down for a ring and valve job. There was a small 4" meandering
"track" in the felt part of the gasket from an oil passage to the
outside world. My guess it was some kind of long fiber that made it's
way into the felt and got gradually eaten away.

I don't know why, but I remember odd/weird crap  like this better than
more important stuff <g>

HG fails are often progressive on the DOHC 2.5L, so if the valvecover
gaskets don't fix the oil leak... get ready for doing that HG job ASAP.

--
"Shit this is it, all the pieces do fit.
  We're like that crazy old man jumping
out of the alleyway with a baseball bat,
saying, "Remember me motherfucker?"
Jim “Dandy” Mangrum

Also check the crank bolt is tight and the crank pulley mount is in
one piece and tight.

Dave

 

[1 Lucky Texan]

Also check the crank bolt is tight and the crank pulley mount is in
one piece and tight.

Dave

Yep, some books in the past evidently had too low torque specs and
folks were having problems with the crank pulley getting loose.

I wouldn't discount the possibility of piston slap. HEAVIER oil should
decrease that but, it never completely goes away. valve adjuster, as
said , is most likely I'd think. Synthetic oil is quite good at
dissolving varnish and keeping it suspended. That's one reason it
looks so black when changed. Might try some walmart supertech w'ever
5-30 with the MMO.

 

[ben91932]

I wouldn't discount the possibility of piston slap.

Piston slap is pretty easy to diagnose in its early stages.
You will hear piston slap most prominently when the engine is dead
cold and under a load, and it will diminish as the engine warms up.
Is this what the OP was experiencing?

 

[hls]

Piston slap is pretty easy to diagnose in its early stages.
You will hear piston slap most prominently when the engine is dead
cold and under a load, and it will diminish as the engine warms up.
Is this what the OP was experiencing?

Hard to say. This engine, if I am interpreting it correctly,
should be a 2.2 litre SOHC H4 boxer arrangement.

I have been curious about these for a long time, but have no
experience with Subaru. They are supposed to be good strong
engines.

I'd like to hear any comments about this setup.

 

[hls]

On the boxer engine, I found this:

http://townhall-talk.edmunds.com/direct/view/.f119459/10

They claim the slap IS typical of this boxer engine.

 

[jim beam]

Piston slap is pretty easy to diagnose in its early stages.
You will hear piston slap most prominently when the engine is dead
cold and under a load, and it will diminish as the engine warms up.

i experienced this for years with honda engines, and was particularly
disappointed when my new 2000 civic started doing it after only 30k miles.

but recently, i tried an oversize oil filter on a high mileage civic
because the motor was particularly noisy, because i figured there was
nothing to lose from better oil flow. i was stunned at the result -
"piston slap" almost entirely gone when cold. looking back on the 2000
civic, the noise started round about the same time i transitioned to the
new smaller honda filter pattern - it would have been interesting to see
what would have happened if i'd gone back to the old size honda filter.
since the old noisy civic discovery, i've tried this on my accord too
- same noisy "cold slap" went away using a larger filter.

bottom line, these new smaller "more efficient" filters may be fine in
terms of performance when the oil is at full working temperature, but i
believe their cold flow characteristics are inferior and restrict flow.
it follows that the noise we're therefore hearing is actually
bearings, not pistons.

i don't know if a larger filter [with larger medium area and thus less
cold flow restriction] is available for subaru, but if it is, for <$7,
it's worth trying. for honda, wix #51344 does the job nicely.

 

[jim beam]

Hard to say. This engine, if I am interpreting it correctly,
should be a 2.2 litre SOHC H4 boxer arrangement.

I have been curious about these for a long time, but have no
experience with Subaru. They are supposed to be good strong
engines.

I'd like to hear any comments about this setup.

i'd like to hear your comments on logical thinking with regard to engine
coolant color.

 

[Nobody > (Revisited)]

Hard to say. This engine, if I am interpreting it correctly,
should be a 2.2 litre SOHC H4 boxer arrangement.

Sorry, this is most likely the DOHC version.

All "H" engines have a propensity for piston slap, it's just the way it
is, but decent designs almost negate it.

Piston slap in a Subaru H4 or 6 is rare, but does happen enough to be
aware of it.


--
"Shit this is it, all the pieces do fit.
We're like that crazy old man jumping
out of the alleyway with a baseball bat,
saying, "Remember me motherfucker?"
Jim “Dandy” Mangrum

 

[hls]

Sorry, this is most likely the DOHC version.

All "H" engines have a propensity for piston slap, it's just the way it
is, but decent designs almost negate it.

Piston slap in a Subaru H4 or 6 is rare, but does happen enough to be
aware of it.

This engine is a 2.2 litre,op says. Offered that year were:
Engine 2.2L SOHC 135 hp (101 kW) H4
2.5L DOHC 165 hp (123 kW) H4


So, it probably wasnt a DOHC.

Piston slap in the Subaru H4 is ANYTHING BUT RARE, of this era.
They are known for it, apparently. It is documented that the slap,\
though loud and unnerving, normally does not limit the engine life.

 

[hachiroku]

Piston slap is pretty easy to diagnose in its early stages.
You will hear piston slap most prominently when the engine is dead
cold and under a load, and it will diminish as the engine warms up.
Is this what the OP was experiencing?

Nope. Idle was the loudest, and it got smoother and a little less
pronounced when run at higher RPMs. Car is not on the road right now.


Definite clicking noise, like a sticky lifter makes.

 

[clare]

On the boxer engine, I found this:

http://townhall-talk.edmunds.com/direct/view/.f119459/10

They claim the slap IS typical of this boxer engine.

Piston slap is generally a light "double knock" that generally
changes with load - just tap the accellerator and let off and it
should change pitch and "quality" or intensity - while a lifter is a
heavier "single knock".

Also, piston slap will be engine speed or double engine speed (double
or singlee knock), while valve will be half engine speed. Piston noise
will generally pretty well dissapear when the engine is warm - and
will not be there on a warm restart. Valve noise may go away when
warm, but usually gets intermittent first - and it often will do a
little "tap dance" at idle even if it has quieted down at fast idle -
and it will often be there on initial hat restart as well.

Not sure about the Sube, but some engines with an oil leak from the
oil gallery will drain the oil from the lifter gallery when shut off,
allowing the lifters to start dry and will take time to pump up and
quiet down. Same problem with some cheap oil filters - the orange ones
I don't need to bother naming are NOTORIOUS for having bad
anti-drainback valves, and OFTEN cause engines to be noisy on a cold
start. VERY often, just replacing the Orange crap with a quality
filter like a WIX /Dana / Etc stops the cold-start noise.

Another test is to remove one plug wire at a time until you find the
one that eliminates or greatly changes the sound. If you find one, it
is a piston (or rod) noise - not a valve....

 

[AS]

Head gasket is very unlikely to fail with the engine not being used.

This motor has hydraulic lash adjusters. When the engine is stopped for
a long while, the adjusters that where under pressure all the time will
leak oil causing the clacking on starting the engine. The reason why
the noise is more noticeable at idle is because the oil pressure is
lower. If you are lucky, the lash adjusters will evacuate the air
inside with repeated use. If unlucky, as with some Nissan Maxima
engines, the only way to get rid of air inside the lash adjusters is by
bleeding the adjusters inside a container full of clean oil.

Sticky valve would be noticeable as a miss on the pressure coming out
from the exhaust pipe.

Other than the nuisance and the "reduced" engine output (if noticeable
at all) the noise wont be too harmful.

Good luck.

AS

 

[clare]

Head gasket is very unlikely to fail with the engine not being used.

This motor has hydraulic lash adjusters. When the engine is stopped for
a long while, the adjusters that where under pressure all the time will
leak oil causing the clacking on starting the engine. The reason why
the noise is more noticeable at idle is because the oil pressure is
lower. If you are lucky, the lash adjusters will evacuate the air
inside with repeated use. If unlucky, as with some Nissan Maxima
engines, the only way to get rid of air inside the lash adjusters is by
bleeding the adjusters inside a container full of clean oil.

Sticky valve would be noticeable as a miss on the pressure coming out
from the exhaust pipe.

Other than the nuisance and the "reduced" engine output (if noticeable
at all) the noise wont be too harmful.

Good luck.

If the lifter is collapsed, driving it will beat the heck out of the
valve stem and lifter, as well as possibly damage the camshaft. I
agree it's not likely a "sticking valve" - but the "sticking lifter"
is very likely - and the MMO solution is the first step.