I'm wondering if someone has a new and very low mileage EJ25 - would it be reasonable to only replace one headgasket? This is not a current issue I'm facing at all. The only one I have now has 300,000 mile with both headgaskets pouring.

 

I can't imagine doing one, just curious.

 

Most say that newer EJ25's are good cars and nothing to worry about.

 

So if only one headgasket is leaking that same logic should apply to the "other" headgasket so to speak if you used the commutative laws of poor reasoning.

 

I might be tempted to do it on my own car, just to save time, not that I currently drive any Phase II EJ25's. But if the other started leaking i'd just wait until the next timing belt change to do it, so not much loss in time really.

It really doesn't save but about half an hour, so I would do it all at once.

right on mike. particularly the Phase II headgaskets are so easy to do, i wasn't thinking about that, they're about the easiest Subaru headgasket. if it was like the Phase I's it might be more tempting! and i was only wondering like certain situations, like 30,000 or something. was talking to someone today in that situation so the thought popped in my head but i didn't say anything like this, just curious.

Since you are pulling the intake off, might as well do them both why go thru all that and then have to do it all over again in 20k when the other one leaks.

Both - no doubt about it. Reseal and you're hopefully set for a very long time.