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The only washers worth replacing are the ones in the water jackets holding the block together, keep that in mind if it ever comes to splitting the case. Head bolts are definitely reusable (as stated above multiple times) no matter what your auto parts store says.
 

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Interesting, per all-wheel drive:

"
Q: Do I need to replace the Head Bolts?
A: If you are unable to check the bolts for stretch then yes, if you have a 2005 and newer, YES"


https://allwheeldriveauto.com/subaru-head-gaskets-problems-explained-part-ii/


I also find it interesting that this is the only site that talks about the eletrical connection to the failed headgaskets and the chemistry associated with the coolant and the importance of keep grounds clean, and coolant maintained to stave off head gasket issues.
 

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So its been about a week since the car is up and running, about 200 miles on it now. Car and engine run beautifully! Still have the undertray off it, couple of times I checked everything is neat and dry under the block.

I will put together the things I learned during the rebuild, some are probably obvious to guys with more experience. Also couple of tricks I was shown to check the engine good before it goes back into the car.

Thanks psygnal11 and everyone who helped with answers. This was my first time ever pulling a motor out or doing anything beyond cover gaskets. Knocking on the wood that car continues to drive as it does now.
 

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Discussion Starter #45
Update (5 years later):

Went to jump start our 04 Forester yesterday (damn parking light switch, amiright?) and while idling, I noticed that both the fans on the Tribeca were on high speed... first time I've heard that since, well, 5 years ago.

So I checked the coolant gauge, and sure enough, it's three boxes above the mid-line. Gave it a couple revs, and the temp came down. Fortunately (read: unfortunately), I knew exactly what I had to do: opened the coolant bottle and listened.... blup, blup, blup, blup, blup.

Although I knew it was an exercise in futility, I tried bleeding the system, even though it's been 6,000 miles since I changed the coolant. So I pulled off the molding over the radiator to access the bleed valve, and what do I see? A fresh, little "honeycomb" of what I can only suspect is Subaru Coolant Conditioner forming at one of the tube joints... sure enough, when I scraped away the top layer, it was wet underneath. [For the record, this does nothing to sway my belief in SCC.]

I hadn't noticed any coolant leaks since the last change, but I bled and filled the warm system, let sit overnight, and when I went outside to open the rad cap this morning: the level in the coolant bottle was lower, but so was the level in the radiator... in other words, it was sucking back both coolant (from the bottle) and air (from the leak). I topped it off, and when I parked the car at work this morning, I could hear the bubbles again. So I'm all but certain it's the same problem as before... combustion gasses are leaking into the coolant passages.

So the engine is coming out, and I'm only doing the HG's and the items for which FSM dictates replacement (the old timing components I took out last time are still sitting on my garage, so it will be interesting to compare the two). Otherwise, I am going to pull the condenser and compressor (since I actually have my 609 and refrigerant recovery equipment now), otherwise, process is going to be the same as last time (save for a new or repaired radiator). My son is actually old enough to help now, so I think I might get this done in <20 hours.

I finished the HG job in 2014 with ~148,500 on the odometer. Current reading... 248,360 :headwall: [I almost made it to 100k].

Granted, if it happened once and happened again, why wouldn't the HG fail a third time? Still unconfirmed (but strongly suspected) is the reason the HG's failed the first time, and I'm already hot on the trail why it's happened now. I'm not going to speculate further right now, but my working hypothesis is that the causes are unrelated. Maybe that's just my ego refusing to say I screwed up the first time... but to go (almost) 100k with nary a hint of any symptoms, at best, perhaps I simply did a B+ job last time: better than expected, but still room for improvement.

I suppose I should look forward to perhaps being the first person to repeat the EZ30 head gasket job separated by (almost) 100k miles.
 

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I feel your pain - I’ve done this job 3 times. First 2 were definitely operator error as I had missed cracked cylinder head and had to redo job straight after first attempt. Third time was 50 k miles later (you beat me) and I think was either related to a ‘lazy’ thermostat or clogged heater core. There’s no doubt that this engine is very sensitive to any overheating and the cylinder heads become warped very easily.
Good luck but you’ll know that it’s much easier second time round and at least the outer timing cover bolts should come out more easily!
 

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Discussion Starter #47
I feel your pain - I’ve done this job 3 times. First 2 were definitely operator error as I had missed cracked cylinder head and had to redo job straight after first attempt. Third time was 50 k miles later (you beat me) and I think was either related to a ‘lazy’ thermostat or clogged heater core. There’s no doubt that this engine is very sensitive to any overheating and the cylinder heads become warped very easily.
Good luck but you’ll know that it’s much easier second time round and at least the outer timing cover bolts should come out more easily!
Spot on, DJB. I'm glad I spent the time to apply anti-seize to any bolts exposed to conditions... probably going to save myself an hour of wrenching right there!

Out of curiosity... after you finished the job the 2nd time, did you reinstall the undercover or did you leave it off?
 

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Spot on, DJB. I'm glad I spent the time to apply anti-seize to any bolts exposed to conditions... probably going to save myself an hour of wrenching right there!

Out of curiosity... after you finished the job the 2nd time, did you reinstall the undercover or did you leave it off?
Yes, after rounding off at least 5 or 6 outer timing cover bolts, I chose to replace all of them with generic stainless steel bolts (same size as OEM).

Regarding the undercover, having re-fitted and removed it about 20 times and cursing the process every time (these wheel arch plastic plugs are an annoyance), I gave up and left it off. Having said that, I had to replace the oil pan recently due to severe corrosion and an oil leak so maybe I could have avoided this work, if it had been left on.
 

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Discussion Starter #49
Yes, after rounding off at least 5 or 6 outer timing cover bolts, I chose to replace all of them with generic stainless steel bolts (same size as OEM).

Regarding the undercover, having re-fitted and removed it about 20 times and cursing the process every time (these wheel arch plastic plugs are an annoyance), I gave up and left it off. Having said that, I had to replace the oil pan recently due to severe corrosion and an oil leak so maybe I could have avoided this work, if it had been left on.
Working theory:

By design, the heads of a boxer engine sit much closer to the ground than in a traditional "V" or OHC/OHV engine. Therefore, at normal operating temperature, they are more prone to thermal shock from road elements (e.g. puddles, splashing, etc.) than engines where the heads sit much higher.

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The afternoon I noticed my temp gauge creeping up (and bubbles in the overflow) just so happened to be a day where we experienced some pretty heavy rains in the morning. On my way to work, I ended up driving through standing water that was a bit higher than I expected it to be (and therefore, I drove through a bit faster than I should), and I recall a pretty big splash on both sides of the car. So if the splash was up to windshield level on the outside of the car, the question is: how much splashed underneath? As you probably have guessed, my undercover was not on the Tribeca that day.

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I went 5 years with no problems, and that's after stressing the engine every which way I could (idling with A/C on full in 90 degree heat, towing a boat, nearly redlining on sport mode every day for a couple weeks straight, etc.) in the first year. I checked the coolant bottle regularly, changed the coolant and ATF at 30k intervals, and oil on 5-6k intervals... so to have everything I experienced prior to the last HG repair manifest within a couple hours of my puddle incident, it's too much of a coincidence to believe it's not related.

I'm very curious to see what the insides look like once I get the engine pulled (i.e. how it compares to what I observed when I opened it up 100k miles ago).

Unfortunately, "Tribeca HG, the Sequel" has been delayed... not as critical given that I sprung for a 2020 Ascent this past weekend. Likely going to be a Labor Day weekend project at this point.
 

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With those fasteners, the key to happiness is having spare ones on hand. But now what, should I be scared of taking the car through a car wash?
 
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