Preventing HG Failure(s)

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To All,

I own 2 NA Subaru Outbacks: '06 & '08 w/ 2.5 Engine which in the past is prone to failure. Supposedly, Subaru fixed the problem in '03 but they still require a coolant additive every 30K.

Nevertheless, I do not believe that they resolve the issue & I've read of sporadic failures on Subaru Boards.

Anyhoo, what are Y'all suggestions of how I can be proactive in order to ensure my HG does not fail?

Regards,
~Button
 
What causes the head gasket to fail? Probably if the problem isn't fixed from the factory maybe there is a high quality Felpro gasket you can install.
 
I'm not sure what cause(s) the failure(s) but my expectations is to get @ least 150K out of the car.

Subaru suggests only using their coolant & additive every 30K. The additive looks like brown clay & I switched to Amsoil Coolant @ 30K.
 
sounds like their "additive" is nothing more than A stop leak pellet. A band aid for their poor design.

Where are the failures most likely to occur? It sounds like its not around the cylinder seal if a stop leak is keeping it running.
 
You need to see if you can get a metal laminate gasket these have multiple layers of different allows and they seal great! I would bet if this is a big problem that one of the gasket makers has just such an animal. I would buy a set and have on hand. If and when it fails have either your shop or the OEM install the higher end after market gaskets!
 
Yea, hopefully I can forgo installing a new HG. So @ the end of the day, there's nothing I can really do to help prevent it?
 
I personally don't believe that a open deck block design is the wisest choice for a high boost engine. I personally feel that this is the cause of many Subaru head gasket failures.
 
Coolant tabs/liquids are common in most modern engines from the factory. They are used to resist weeping from any joint in the cooling system. HG failure is extremal rare in late model Subaru's.
 
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The N/A models fail also; my Subie buds have had good results with Cometic head gaskets in their high powered builds. Recently had one break a (stock)rod at 28 psi and about 400+ HP and the head and gasket was intact! Crankcase is tosat , but the upper end held up
HTH
Jorge
 
Originally Posted By: Eddie
Coolant tabs/liquids are common in most modern engines from the factory. They are used to resist weeping from any joint in the cooling system. HG failure is extremal rare in late model Subaru's.


I don't know what kind of cars you work on, but I have only seen one manufacturer use stop leak tablets at the dealership.

This is why I will NEVER buy anything from General Motors.
 
Ford dumped them in the coolant tank of my 2002 excursion. Its the reason the factory fill G-05 turns dark after a few thousand miles.

Might also be why the water pump shat the bed on that one @50,000 miles.
 
Have a workmate with a few year old subie that perked all it's coolant into the overflow bottle last week.
 
Originally Posted By: Button
Just a heads up but Subaru Turbo Engines HG are less prone to failure than NA.


If the heads and block are the same, I assume they used better gaskets and bolts for the turbo models? If you can confirm the bolts are different, maybe you could swap the bolts, taking one out at a time with the "turbo" bolts. I've seen problems with some TTY bolts stretching over time and relaxing the gaskets.

We would have to know the reason for the failures to figure out a solution. I've only blown headgaskets from detonation so make sure you run enough octane to prevent knock.
 
are they failing the headgasket or slow coolant leaks evolving over time??

Do they offer an improved HG from a performance parts vendor?

For our chrysler 2.2/2.5 Turbos MP Performance offers a good headgasket repalcement either for cross drilled heads or the early non-crosdrillled. Will hold 30 PSI of boost if you dont detonate.

Does your T-stat open all at once and shock the head with cold coolant? If so drill a small 1/16 hole in the t-stat to bleed some coolant. It wont theramlly shock the head.
 
'96 to '99 were the bad ones, they would leak internally and pressurize the coolant and puke it out the overflow. Later models will typically leak externally and you'll see/smell coolant before any bad overheating happens.

Too bad we don't get the relatively bullet proof ej22 anymore. The ej25 seems to have made headgaskets a part of regular maintenance!
 
I use the Conditioner (stopleak). I would suggest using it along with the Subaru coolant and forget. Leaks can and will happen. Subaru has 2 head gaskets so statistically it will have twice the HG leaks.

Do an oil analysis periodically.
 
Subarus have always had HG problems from the very beginning. I worked in service at a Subaru dealership in the late 70s and we did non-stop HG replacements back then. It's the design of the engine that's at fault.

If you know it is a weakness, then always plan to have them replaced at 100k intervals and enjoy all the other benefits of Subaru ownership. Better yet, learn how to do it yourself and save lots of $$$$
 
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