--
  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.