As preventive maintenance I'm replacing the head gaskets on our 09 Forester with 140'000 miles. The gasket set I revived is a Stone gasket set. I am old school and haven't ever heard of them. How is there Quality and do i want to use them. Also does anyone know what the torque sequence is? 

I usually read about Cometic, SixStar and OEM of course . Never read of Stone.

Use ONLY the Subaru OEM 642 or 770 gaskets for the turbo models. Don't use anything that is sold for your engine. Nothing else will work long term, and nothing else will provide better sealing than the 770. 

GD

What he said. 

Can you look and see if they’ve been replaced before?  

Thank you all for your advise guess I will be going with oem. But there is one thing that puzzles me since there is an issue with the original gaskets that causes them leak around 150,000 miles. so have the oem gaskets been improved or will i be replacing them in 150,000 miles again?

The gaskets have not been replaced before. We are the original owners and this has been a very low maintenance vehicle.

  Thanks again for all of the support.

 

You will not be using the gaskets that are original to that engine. You will be ordering gaskets for a 2006 STi. Part number ending in 642 or 770. They are entirely different gaskets from what was used on your model from the factory. Your engine didn't get these gaskets till 2011. 

GD

16 hours ago, utcoyotehunter said:

Thank you all for your advise guess I will be going with oem. But there is one thing that puzzles me since there is an issue with the original gaskets that causes them leak around 150,000 miles. so have the oem gaskets been improved or will i be replacing them in 150,000 miles again?

The gaskets have not been replaced before. We are the original owners and this has been a very low maintenance vehicle.

You're installing a different gasket. 

There is probably a chance of the newer gasket leaking by 150,000 miles but they hold up much better than the 09 gaskets.  the newer 2010/2011 EJ25's that came with updated gaskets have a presumably much lower rate of failure and it's different - they push exhaust gases into the coolant and overheat, unlike your 2009 which will never do that - it'll just leak externally. 

The statistics are really low - but you probably have more chance of issues repairing it than if you don't.  The repaired gaskets have a small chance of stranding you and introduce a (tiny) potential for user error, the current gaskets do not have any additional risk by leaving them.  For that reason there is zero gain in doing the gaskets preventatively in most situations.  

If they're known original gaskets I'd leave them be unless the engine is coming out for something else or you're going in for massive surgery that takes 2 years to recover from.  Otherwise the headgaskets start leaking slooooooowllllllllly and can not cause any issue or failures at all, it's impossible.  At first the metal around the headgaskets just gets slightly discolored, like a mole on your skin.  It just looks like grease at first, you can't even tell it's oil by looking at it. Then it gets bigger and bigger and a few months later it forms it's first drip.  Then the drips will get worse over time - in any event - you have months from the first sign of wetness on the block/head to plan a repair like you're doing now. 

It's not like they "blow" in the traditional sense of overheating, oil/coolant mixing, or blowing coolant out the exhaust pipe and could strand you - none of that is a possibility with this engine.

 

Edited November 27, 20187 yr by idosubaru

Thank you all for your help and advice. Idosubaru if i had known that i certainly wouldn't have replaced the gaskets on a preventive maintenance program. Thank you for the education that would have taken me hours to write that S.A.

Tiny percentages, no big deal.  Now you’re all done and have the new gear in there , good stuff.