2.5L Engine and Gasket Problems

[The_Big_Muddy]

I just launched http://www.subaruproblems.com a website dedicated to
gathering and presenting information on head gasket and coolant leaks
in the 1999 - 2002 Subaru's. Did it happen to you? please share your
story with us.
Thanks in advance.

Brian
http://www.subaruproblems.com

 

[Pete2000]

I have a '00 Legacy Wagon with 46K miles that had a leaky gasket. I took
it to the dealer last Wednesday and on Thursday they replaced the gaskets
(removed entire engine) at no charge. I am extremely pleased with how
Subaru took care of me.

 

[Cro 33]

I have an 01 Legacy GT 50K both head gaskets went. Dealer fixed
it under recall warr.

 

[Mickey]

I just launched http://www.subaruproblems.com a website dedicated to
gathering and presenting information on head gasket and coolant leaks
in the 1999 - 2002 Subaru's. Did it happen to you? please share your
story with us.
Thanks in advance.

Brian
http://www.subaruproblems.com

Will be getting my 00 obw back in a few days with new HG and new
seals. 124k miles so bill is on me.

The gasket just started leaking externally, left, rear. Could only
spot coolant on a few bolt heads on the xmember and drop in the
overflow tank.

Mickey

 

[jabario]

Does any maker cover a gasket leak at 124k? I dont think so. How many
people get 200k on a subie without major problems.

 

[Pete2000]

I thought Subaru was covering the gasket leak problem for eight years
regardless of miles. What did the recall letter say?

 

[4WDGL]

Does any maker cover a gasket leak at 124k? I dont think so.
How many
people get 200k on a subie without major problems.

Is there any differance between the head gaskets used in the years
recalled and the 2003 model year with the 2.5L engine? My ’03
Forester has smelled like coolant for a while now so it’s possible
that it’s also starting to leak.

 

[Mickey]

Is there any differance between the head gaskets used in the years
recalled and the 2003 model year with the 2.5L engine? My ’03
Forester has smelled like coolant for a while now so it’s possible
that it’s also starting to leak.

My understanding from info provided by the inde shop I'm using says
they are on the 3rd design of the gasket. Good thing is shop says
they have never have seen a failed gasket with the latest design.

My understanding is the problem yrs for head gaskets was 2.5L engines
up to 2002 model yr.

Mickey

 

[Mickey]

I thought Subaru was covering the gasket leak problem for eight years
regardless of miles. What did the recall letter say?

8 yrs, 100k miles.

IMO the conditioner Subaru wants you to use is just a "stop leak" that
will likely get you out past the extended warranty period.

A post I read yesterday was saying they had HG problem at 70-80k miles
and took it in to the dealer and thought new HG had been installed.
Some months later and slightly more than 100k miles, the leak appeared
again. Took the car back to the dealer and was then informed all that
was done first time was put the stop leak in. Since leaking past 100k
miles, the bill was on the owner. NOT GOOD!

Mickey

 

[mutant_dan]

Here is some helpful info on headgaskets..

From: Gene Goldenfeld <genegold@h...
Date: Thu Jan 13, 2005 8:06 pm
Subject: Re: [outback] Head Gasket failure info on Subaruvanagon
mailing list


dyerlytle wrote:

There is an interesting discussion about head gasket failure in 2.5L
Subaru engines over on the subaruvanagon mailing list. (This is a
mailing list for people with VW Vanagons who have swapped in a Subaru
engine to replace the VW water boxer.)

Indeed. In the interest of getting the discussion over here (and
providing me a copy to archive), I've copied Al Wick's posts on head
gasket failure from the Subaruvanagon group. I let him know.

Gene
-------------

I was in unusual situation where I was able to find the head warp
"gasket fail" problem before the dealers were getting any failures.
Many years ago I adapted a new 2.5 (10k miles) to my airplane. I have
sensors galore on the plane, so when the head first started leaking, I
was able to look at the data on my laptop and see that the head leaked
pressure to coolant system 3 seconds after I hit full throttle. It then
dissipated 5 seconds later. I really learned a lot and deliberately
operated at full throttle for long periods (hour or two). All the time
logging the pressures and temps every few milliseconds.

So here's the deal. All failures are caused by air in the cooling
system. No air, no problem. If you have air bubble AND you operate at
high throttle settings, the head will warp. It takes a long time to
show up. So if there was trapped air 6 months ago, then you might now
start to see discolored coolant, overheating. Or it might only occur
climbing a hill in hot weather. Only the 2.5 has this marginal
condition. All other Subaru's bullet proof.

My flying partner makes a living replacing gaskets on 2.5's these days.
Number one repair item. It appears that the 2.5 has an area at center
of block/head interface which doesn't have enough coolant flow. When a
bubble passes by, it boils locally. This eventually causes head to
warp, gasket to give out. Subaru has tried 3 different style gaskets,
even adding coolant conditioner to improve heat transfer. Still a
problem. But absolutely all failures caused by trapped air in system.
All models of 2.5 liter the same.

The solution is very simple. Just drill and tap your coolant crossover
pipe and add a fitting that allows air to leave engine and rise to your
swirl pot. You will never have a problem. I operate my engine full
throttle for hours at a time. Fabulous engine.

-al wick

--------------
I got a couple other private messages regarding the same. I'll try to
clarify...

The crossover tube is the aluminum coolant tube that lives under the
intake manifold. It's rectangular in shape and the main coolant hose
attaches to one end of it. It's the one everyone reverses. I'm unable
to say there is a "best place" to add a fitting to the tube. Likely it
does not matter where you place the fitting. Just somewhere in the top
of this tube. The fitting needs to be on this cross over tube because
this is the highest point in the ENGINE cooling system. Your goal is to
purge any air that happens to be in the engine. This is different than
purging air from your radiator or from your heater core. Air in the
engine causes head warp. Air in other components just reduce their
efficiency. We imagine that air flows with the moving coolant, but
actually it only does to small degree.

Drill and tap this tube. Install a fitting, and run hose from that
fitting to your swirl pot. No dips in hose, it must gradually rise to
swirl pot. As long as the swirl pot is above the engine it will
automatically purge all air from the engine. This results in a "robust"
cooling design. Robust meaning it handles unusual conditions. If your
brother in law borrows your vehicle, blows a hose, and doesn't realize
he needs to bleed air, no problem. Because your system automatically
purges all air from engine.

 

[Jim Stewart]

The crossover tube is the aluminum coolant tube that lives under the
intake manifold. It's rectangular in shape and the main coolant hose
attaches to one end of it. It's the one everyone reverses. I'm unable
to say there is a "best place" to add a fitting to the tube. Likely it
does not matter where you place the fitting. Just somewhere in the top
of this tube. The fitting needs to be on this cross over tube because
this is the highest point in the ENGINE cooling system. Your goal is to
purge any air that happens to be in the engine. This is different than
purging air from your radiator or from your heater core. Air in the
engine causes head warp. Air in other components just reduce their
efficiency. We imagine that air flows with the moving coolant, but
actually it only does to small degree.

Drill and tap this tube. Install a fitting, and run hose from that
fitting to your swirl pot. No dips in hose, it must gradually rise to
swirl pot. As long as the swirl pot is above the engine it will
automatically purge all air from the engine. This results in a "robust"
cooling design. Robust meaning it handles unusual conditions. If your
brother in law borrows your vehicle, blows a hose, and doesn't realize
he needs to bleed air, no problem. Because your system automatically
purges all air from engine.

What and where is the "swirl pot"?

 

[mutant_dan]

What and where is the "swirl pot"?

The Swirl Pot is a mystery to me as well. It might be a British term or
aircraft thing. I have e-mailed Al Wick for more details..

Here is a link to the Al's webpage:

http://www.maddyhome.com/canardpages/pages/alwick/engine.html

Where he states:

It's essential that the 2.5 liter coolant crossover tube atop the
engine be drilled and tapped. This allows user to add a small tube from
there to the coolant reservoir.

-----------

And from a recent post in another forum it looks like doesn't recommend
using the overflow. Is there a difference between the overflow and the
coolant reservoir?

-----------
1st.Only air in the block and higher power settings will cause the head
warpage. Every single occurrence (per my mechanic source) is traced
back to the owner changing the coolant and not knowing how to purge the
air.

2nd. It's a design oversight by Subaru. Due to sloping hood and vehicle
height, the air in block can't move to radiator. It stays in block. The
radiator isn't mounted high enough relative to engine. There are a
number of other manufacturers that have this problem, without the head
warping. They just overheat until customer takes it to dealer and he
burps it. Some place a bleed valve at the engine block. Just open valve
until water starts coming out, close it.

True, you would not want to run the tube to overflow. Your cooling
system would then no longer be under 7 psi it normally is during
operation. You just want the air in block to move higher and out of the
coolant flow. My bleed line is the most robust approach, but you could
also just make sure you loosen hose clamp until fluid comes out. That's
what dealer does.
----------------------------------------

 

[Gilles Gour]

Here is some helpful info on headgaskets..

From: Gene Goldenfeld <genegold@h...
Date: Thu Jan 13, 2005 8:06 pm
Subject: Re: [outback] Head Gasket failure info on Subaruvanagon
mailing list


dyerlytle wrote:

There is an interesting discussion about head gasket failure in 2.5L
Subaru engines over on the subaruvanagon mailing list. (This is a
mailing list for people with VW Vanagons who have swapped in a Subaru
engine to replace the VW water boxer.)

Indeed. In the interest of getting the discussion over here (and
providing me a copy to archive), I've copied Al Wick's posts on head
gasket failure from the Subaruvanagon group. I let him know.

Gene
-------------

I was in unusual situation where I was able to find the head warp
"gasket fail" problem before the dealers were getting any failures.
Many years ago I adapted a new 2.5 (10k miles) to my airplane. I have
sensors galore on the plane, so when the head first started leaking, I
was able to look at the data on my laptop and see that the head leaked
pressure to coolant system 3 seconds after I hit full throttle. It then
dissipated 5 seconds later. I really learned a lot and deliberately
operated at full throttle for long periods (hour or two). All the time
logging the pressures and temps every few milliseconds.

So here's the deal. All failures are caused by air in the cooling
system. No air, no problem. If you have air bubble AND you operate at
high throttle settings, the head will warp. It takes a long time to
show up. So if there was trapped air 6 months ago, then you might now
start to see discolored coolant, overheating. Or it might only occur
climbing a hill in hot weather. Only the 2.5 has this marginal
condition. All other Subaru's bullet proof.

My flying partner makes a living replacing gaskets on 2.5's these days.
Number one repair item. It appears that the 2.5 has an area at center
of block/head interface which doesn't have enough coolant flow. When a
bubble passes by, it boils locally. This eventually causes head to
warp, gasket to give out. Subaru has tried 3 different style gaskets,
even adding coolant conditioner to improve heat transfer. Still a
problem. But absolutely all failures caused by trapped air in system.
All models of 2.5 liter the same.

The solution is very simple. Just drill and tap your coolant crossover
pipe and add a fitting that allows air to leave engine and rise to your
swirl pot. You will never have a problem. I operate my engine full
throttle for hours at a time. Fabulous engine.

-al wick

--------------
I got a couple other private messages regarding the same. I'll try to
clarify...

The crossover tube is the aluminum coolant tube that lives under the
intake manifold. It's rectangular in shape and the main coolant hose
attaches to one end of it. It's the one everyone reverses. I'm unable
to say there is a "best place" to add a fitting to the tube. Likely it
does not matter where you place the fitting. Just somewhere in the top
of this tube. The fitting needs to be on this cross over tube because
this is the highest point in the ENGINE cooling system. Your goal is to
purge any air that happens to be in the engine. This is different than
purging air from your radiator or from your heater core. Air in the
engine causes head warp. Air in other components just reduce their
efficiency. We imagine that air flows with the moving coolant, but
actually it only does to small degree.

Drill and tap this tube. Install a fitting, and run hose from that
fitting to your swirl pot. No dips in hose, it must gradually rise to
swirl pot. As long as the swirl pot is above the engine it will
automatically purge all air from the engine. This results in a "robust"
cooling design. Robust meaning it handles unusual conditions. If your
brother in law borrows your vehicle, blows a hose, and doesn't realize
he needs to bleed air, no problem. Because your system automatically
purges all air from engine.

Could someone explain what a "swirl pot» is??

 

[mutant_dan]

I am tracking the Swirl Pot at this location.

Check it out...
http://www.ultimatesubaru.net/forum/showthread.php?t=28600

 

[Jim Stewart]

The Swirl Pot is a mystery to me as well. It might be a British term or
aircraft thing. I have e-mailed Al Wick for more details..

Here is a link to the Al's webpage:

http://www.maddyhome.com/canardpages/pages/alwick/engine.html

Where he states:

It's essential that the 2.5 liter coolant crossover tube atop the
engine be drilled and tapped. This allows user to add a small tube from
there to the coolant reservoir.

I think he's really on to something. The 2 times
I've replaced the coolant, I've been on pins and
needles as I watched the temp gauge go above it's
normal position while trying to bleed the air out.

I think that you could install a 1/8" copper line
from the crossover tube, through a little needle
valve and then into the coolant reservour. Just
cracking the valve periodically with the engine
hot should purge the air bubbles. No big deal
and not a big hassle to install.

 

[Dominic Richens]

I think that you could install a 1/8" copper line
from the crossover tube, through a little needle
valve and then into the coolant reservour. Just
cracking the valve periodically with the engine
hot should purge the air bubbles.

Sorry for my ignorance, but isn't this what the pipe from the radcap to the
overflow bottle suppose to do? Is the point of all this that this pipe is
not in the right place to bleed all bubbles from the engine so we have to
add another one?

cheers!

 

[Jim Stewart]

Sorry for my ignorance, but isn't this what the pipe from the radcap to the
overflow bottle suppose to do? Is the point of all this that this pipe is
not in the right place to bleed all bubbles from the engine so we have to
add another one?

That pipe is too low to get the air out. A bubble
forms above it and there's no way to get it out.

 

[-rick-]

The Swirl Pot is a mystery to me as well. It might be a British term or
aircraft thing. I have e-mailed Al Wick for more details..

Here is a link to the Al's webpage:

http://www.maddyhome.com/canardpages/pages/alwick/engine.html

from that site:

 

[Danny Russell]

SNIP
2nd. It's a design oversight by Subaru. Due to sloping hood and vehicle
height, the air in block can't move to radiator. It stays in block. The
radiator isn't mounted high enough relative to engine.
SNIP

I'm noticing that this thread isn't differentiating between specific model years or phase I or phase
II designations.

I just went out and took a look under the hood of my '02 OBS 2.5, and what I see is:

---------------------------------------------------------------------------
1. The engine IS positioned at a slight upward attitude (front IS higher than the rear).

2. The highest point of the crossover tube IS the exit end (hose end).

3. The upper radiator hose IS positioned in a slight incline as it makes it's way to the upper tank
which visibly IS easily the highest point of my cooling system.

Essentially, my vehicle has a complete uphill path for air exit.

To top it off, when I purge/burp my cooling system, I have the front of the car up on ramps which
effectively doubles the incline of "air rise" out of the system. Yet during normal operation after
the system is closed back up, I still get a slow stream of air bubbles out of my overflow tube after
the engine reaches full operating temperature. The bubbles do not stop, they will continue week
after week, month after month.

I've been watching this phenomemon for 4 years now. Can anyone explain this?>

 

[Mickey]

I'm noticing that this thread isn't differentiating between specific model years or phase I or phase
II designations.

I just went out and took a look under the hood of my '02 OBS 2.5, and what I see is:

---------------------------------------------------------------------------
1. The engine IS positioned at a slight upward attitude (front IS higher than the rear).

2. The highest point of the crossover tube IS the exit end (hose end).

3. The upper radiator hose IS positioned in a slight incline as it makes it's way to the upper tank
which visibly IS easily the highest point of my cooling system.

Essentially, my vehicle has a complete uphill path for air exit.

To top it off, when I purge/burp my cooling system, I have the front of the car up on ramps which
effectively doubles the incline of "air rise" out of the system. Yet during normal operation after
the system is closed back up, I still get a slow stream of air bubbles out of my overflow tube after
the engine reaches full operating temperature. The bubbles do not stop, they will continue week
after week, month after month.

I've been watching this phenomemon for 4 years now. Can anyone explain this?>

Thought this would be a good spot to add my comments.

Water exits the engine from mid-point and with engine mounted as noted
above, I would think trapped air would be at front of the engine.
Have noted and done so my self, had car on ramp to increase the angle
during purge. Seems like this would be cause for more trapped air.
And to add fun to the discussion, most common location for external
leak on phase II engines is the lower aft left side. Seems to me like
this would be the most unlikely spot for "trapped air" and why is the
left side more prone to fail?

Will be picking up my car in a day or so and will talk to the shop
owner as to his thoughts on trapped air being root cause for failures
and reason for failure location.

Mickey