Anybody have experience with a failed Suburu Head gasket.
   Milo was on the way from Washington to Texas and made it as
   far as SZP. Then the Soob engine had a mysterious over heating
   problem towing a trailer.

   Paul Lamar

   No experience with Soob and blown head gasket, but with a Dodge
  Minivan, I
   had an overheating problem that seemed 'mysterious'.

   It would overheat, and when you checked the coolant reservoir it
  would be
   full. When the engine cooled, the reservoir would go down as expected.

   The problem was a small leak in the head gasket, which would put
  combustion
   gas into the cylinder space, driving the coolant out of the
engine and  into   the overflow reservoir.

   Bill Schertz
   KIS Cruiser #4045
   N343BS

   Bill, did you try any chemical sealants such as duraseal or steel
seal?

   Paul Lamar

   Yes I have as that is my business and I rebuild 3 to 4 engines a
  week, no
  none of those sealants will work as the problem is the combustion
  pressure
  is pushing past the gaskets into the water system and pushing the
  water out
  the burp tank and so there is no way to plug the leak unless you could
  get
  the sealant into the combustion chamber to shove it into the hole thats
  leaking, hate to say it but you are best to go for a whole engine
as  you can  mill the heads when you replace a head gasket but you
cannot mill the  block  and the block warps as much or more than the
heads so if you put a new  gasket on a straight head and a warped
block it wont last long, I can  do a  compete long block for $1500
to $1600 depending on which engine it is  and I  fix all the
problems that Subaru had to make it better than new.  Give me a call
if you need more info.  Ken

   360-834-4089

  I don't know which engine is in that Subaru, but my sister has one
and it  had a bad head gasket and this is a known problem.  They
have an improved  replacement gasket that fixes it but they didn't
do a recall and  replace it  on their dime.

  Steve Brazil

  The good news is as far as Milo and family are concerned is they were
  able to plug
  the leak with goo. After the engine cooled off it sucked all the
  coolant back
  out of the over flow can. That would not have happened if the leak
  still existed.
  That is part of the process. If the exhaust valve and intake valve
is  closed  hot air in the cylinder cools off causing a low pressure
in the  cylinder drawing  the sealant into the leak. This is
somewhat of a crap shoot as the  leak must  occur around the
cylinder that happens to stop in that sealed condition.  Also of
course the coolant itself also contracts drawing coolant in  from
the  over flow can.

  There has been several recent breakthroughs in these stop leak type
  fluids.
  Prior to these breakthroughs most stop leak type products required
you  to purge  the engine of antifreeze coolant. This is no longer
true of the better  products.  The other breakthrough is a chemical
reaction that is triggered by the  high  400 to 500 F metal
temperatures that causes the goo to solidify in the  area  of the
leak but not in the radiator.

  Here is the web site that claims to be the best.
  It is called Steel Seal. It is a clear liquid with no particulate matter
  at all. It is rather expensive at $70 and they claim to have an
iron clad  patent. "The product is drawn into the damaged area and
seals the crack  with a thermo-chemical bonding process."

  I have not tried it on a leaking rotary yet but
  it sounds promising to fix the shrunk rotor housing problem due to
  extreme over
  heating of the rotary. Milo has some on order to test it on the
soob  if the  stuff we actually used fails.

  https://secure.steelseal.com/index.php/t2b

  Paul Lamar

   Re  Overheating Soob.   Most Subaru's only have electric fans and
  sometimes the switch in the radiator fails to switch on and causes
a  overheating porblem, can happen if people turn off the air/con, because
  the air/con turns the fans on even if the engine is not hot, then
  without the air/con turned on the fans  you have NO fans at all!!
   Can also have a overheating problem only when towing because the
  radiator tubes are partly blocked internally, and so not enough reserve
  cooling available, so the engine overheats, will also happen if the
  radiator cap is not holding at least 14/15 psi.
    John Burey

  It was definitely a head gasket. IMHO here is why head gasket problems
  on the Soob are common. Not enough head bolts. Too much distance
  between bolts allows the aluminum head to deflect between bolts.

  Paul Lamar

  Here is the Chevy LS1 V8 head bolt spacing with about the same bore
  and center to center spacing. Also with an aluminum head.
  LS1 head gasket failures are less common.

  The Soob engine needs to be redesigned.

  Paul Lamar

  Ken

In the case of the Soob, unlike the rotary, the strength or stiffness
of the studs does not help much.

Consider the cylinder head a simply supported beam. Deflection is
proportional to the cube of the distance (l) between the bolts.


http://www.codecogs.com/reference/engineering/materials/beams/simply_supported_beams.php

A reduction in stud spacing from 4 inches to 3 inches will halve the
head deflection. 4 cubed is 64 while 3 cubed is only 27.

Paul Lamar

I use ARP head studs on my race engines and offer them to people with
grocery getters for extra insurance, with these studs they will
handle 45 lbs of boost at 700 plus hp, for more boost you can tap
out the case and run oversize studs as the next thing that will
happen to the threads will pull out if your replacing the head
gaskets get the original OEM multi layer steel gaskets from Subaru
and if its a 2.5  ask for the gaskets for a 97 outback regardless of
what year it is, that is the gasket that I put on all my engines
including the turbo engine, also spray the head gasket with permatex
copper spray, with that it should get you home but it will probably
give problems latter as chances are that the case, heads and
cylinders are warped if it has overheated and that is why I mill the
case and heads and bore the cylinders 20 over on all the engines I rebuild.
Ken

  I just thought of something else, for parts in your area go to Outfront
motor sports, they would have the ARP head studs there and that
would really help in your case as you torque them much higher than
the stock bolts.

Lots of engines have 4 bolts per cylinder with aluminum heads, some aluminum
blocks that do not have a lot of problems. I would be looking at the amount of
metal in the head and around the bolt holes in the block. Modern automobiles
are being subjected to weight reduction to get better fuel economy. Less mass
to accelerate results in lower fuel burn. It looks like Mazda took 400 pounds
out of the 3 this year a lot of it using high strength steel in the body and
design software to put metal where you need it and not in un-necessary places.
Years ago Detroit Diesel built an engine with free standing liners. Nothing
but gasket problems. Tried drilling out head bolt holes eventually from 14mm
to 15mm. In a diesel with the side loads on the piston during the power stroke
it is a bad design in my opinion. The engines that run for years at max power
have metal in them and weight is high. Design too light for the application
and you shoot yourself in the foot. Every now and then a new sharpie comes
along that is going to show everyone how smart they are(red necks!!!) and
usually shoot both feet eventually.
I am thinking Soob took a bit too much metal out. Time to go back to what did
work!!!

Dale Davies