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Old 09-13-2017, 06:23 PM   #1
03SubyWRX
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Default Head Gasket for EJ253?

Hi Guys -

I have a 07 OBS with the EJ253 that has bad valve seals. I picked up a spare set of heads, had my machine shop go through them (valve job, new springs/seals/guides, and decking), and I sent the cams out to Delta for their torque grind.

I am trying to choose what head gasket to use. I don't want to use the OEM Subaru EJ253 gasket because it's still a ****ty single layer design. I'm looking at either the OEM Subaru EJ257 gasket (04 STi, don't have the PN atm), or the Cometic gasket for the EJ253 since both of these gaskets are MLS.

I understand the OEM Subaru EJ257 is thinner than the EJ253 gasket. Will this be an issue in terms of piston and/or valve clearance? Again, I'd prefer to use an OEM gasket, but if piston/valve clearance is an issue with the OEM Subaru STi gasket then I will go with the Cometic gasket.
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Old 09-15-2017, 06:22 PM   #2
03SubyWRX
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Bump, looking for advice.
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Old 09-15-2017, 07:24 PM   #3
Preludicrous
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I'm pretty sure you can use the STi gaskets with no issue. It's been discussed in this forum before, you can probly find at least a couple threads about it.
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Old 09-16-2017, 12:41 AM   #4
93stiImperza
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For the ej253 oem headgasket they do make a updated 3 mil gasket. I was able to find update part# Just bout a set thru ebay a few months back for a side job. Or go with a felpro set they as make a et to.
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Old 09-19-2017, 08:46 PM   #5
Bluefoton
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The Sti one should work. Part nr.... 642. That's the one I used when mine blew on my old EJ251 - it's a MSL design.
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Old 09-20-2017, 04:09 AM   #6
terrainasaurus
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bump. me interest 2
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Old 09-21-2017, 12:14 AM   #7
jamal
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Yeah use 11044aa642.

Newer ej25s, like 09+ have different passages in the heads so you need to use the 07+ sti gaskets. I think it's the same part number between the n/a and turbo cars anyway. ...770 I think.
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Old 09-22-2017, 11:24 PM   #8
03SubyWRX
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Thanks for the help guys
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Old 09-23-2017, 02:15 PM   #9
Bluefoton
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Quote:
Originally Posted by jamal View Post
Yeah use 11044aa642.

Newer ej25s, like 09+ have different passages in the heads so you need to use the 07+ sti gaskets. I think it's the same part number between the n/a and turbo cars anyway. ...770 I think.
So the HG number changed in between EJ251 and EJ253 - and along with it, the "equivalent" Sti one?
I'll need a confirmation, since I'm mentally preparing myself for mine to fail....
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Old 09-23-2017, 05:24 PM   #10
jamal
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Well, the gasket did change, a bunch, now that I'm looking at the parts catalogs. Almost every year from 03-08 - 521, 631, 632, 633. But they all supersede to the same number - 11044AA633, up to the 2011 impreza, which I think was the last year of the EJ in them. And those gaskets have the older coolant passage holes, and still appear to be black/coated gaskets, not MLS like the turbo cars.

However, the outback uses part 11044AA770 for 2010, which is the same gasket as the 2008+ STI. It is the same thickness and construction as the 04-06 gasket but has different cooling holes (there was also an 07 sti only gasket).

So maybe the 2010 outback/legacy and impreza heads are a little different?

Anyway, I guess you would want to look at the heads to determine whether to use 642 or 770. It appears that any impreza 99-11 and legacy/ob 99-09 you would want 642. Then 2010+ legacy/outback with an EJ, use 770.
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Old 09-23-2017, 05:56 PM   #11
kos
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FINALLY rebuilding my tired EJ253, 206,125 on it and its been long due for HGs. Going to go the 642 route.
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Old 11-09-2017, 03:23 PM   #12
terrainasaurus
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Just making sure.. will the 11044aa642 work with a 2008 OBS? Cooling passageways will not be affected?
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Old 11-12-2017, 10:36 AM   #13
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anecdotally, on my 07 2.5i I believe I had the equivalent year oem STI gasket put on when I had mine done at only 100k km. Since the block on the sti hasn't changed, I would assume that all sti gaskets would be the same in terms of coolant passages. My mechanic said I would be able to use the STI gasket without issue, as he had done several with it. For those in the NCR in canada, the mechanic was rocky. The gakset held up without further issue (no machining of the heads done), though I believe there was the typical sweat occuring.

Rocky noted my HG leak was on the passenger side, rather than the more common driver side.
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