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Old 09-25-2018, 12:18 PM   #1
bigredscowboy
Scooby Newbie
 
Member#: 442121
Join Date: Mar 2016
Location: High Point, NC
Vehicle:
1999 Impreza Outback
Red

Default 2.2 (EJ22) head gasket p/n and 2.5 alternates?

I have one of the rare 2.2 with blown head gasket. Fel-pro blue mls failed after 35k. So it’s back out. I had a set of sti gaskets (11044aa642) and everything lined up. Simple google search gave me this:
https://forums.nasioc.com/forums/showthread.php?t=1713699
Quote:
Originally Posted by Marnix View Post
All OEM headgaskets after 1999 are MLS; ie. 2.5 SOHC and 2.5 DOHC Turbo (11044AA641 - 0.58 mm thickness); 2.0 DOHC Turbo (11044AA483 - 0.8 mm thickness); 2.2 SOHC (11044AA542 - 0.8 mm thickness) and even the replacement 1996-1998 2.5 DOHC (11044AA610 - 1.4 mm thickness).

All these gaskets have the same pattern for coolant passages which means they won't work on pre-1999 SOHC heads (except 1991-1994 2.2 Turbo).
So this was from 2009. STI AA642 mic’ed out at 0.8mm for me, so I used it (old Felpro was also 0.8mm). Called my people at Subaru and they said the present 2.2 p/number is still 542. 2004 2.5 N/A is 632 and/or 633. He didn’t have a thickness spec. Rep said it was possible that all the gaskets are the same thickness.

So did Subaru add some thickness to the sti (642) over the last decade or was the above DOHC turbo a wrx only measurement (641 @ .58mm)?

Also, will I have any valve interference or tensioner problems if my guage was wrong and the 642 was actually 0.58mm when it needs 0.8mm (or more for the .001” I shaved off)?
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Old 10-01-2018, 03:20 PM   #2
bigredscowboy
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Member#: 442121
Join Date: Mar 2016
Location: High Point, NC
Vehicle:
1999 Impreza Outback
Red

Default

I ended up at Subaru and purchased a set of 633’s. These are for the 2.5. Just wanted to add info for posterity. They are single layer @ .8mm

Compare this to the 642 which is mls (three layers) @ .8mm also.
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Old 10-01-2018, 04:09 PM   #3
Charlie-III
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Member#: 30669
Join Date: Dec 2002
Chapter/Region: Tri-State
Location: USA, North NJ, 07456
Vehicle:
1998 Legacy 2.5GT
Silver Sleeper BK, 5MT

Default

Thanks for the info.

Do you have an Outback (guessing no, thought 99 was 2.5L) or OBS (Outback Sport, Impreza based, NOT Legacy based)?
We owned (from new) a Impreza L wagon, 2.2..... yes, we lost a HG. Myself and others didn't believe it either.

I tend to just use the current USDM dealer HG, I shy away from aftermarket on some cars, like Subaru.
Not saying others are bad, just saying what I do.

I would "prefer" the correct current HG PN for the VIN assuming the engine is original.
Will yours work?
Maybe.

Assume ALL Subaru engines are interference. There are ways to check, but I err on the side of caution, even though I do a lot of my own work.
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Old 01-14-2025, 10:07 PM   #4
Sforester
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Member#: 540036
Join Date: Jan 2025
Default Question

Quote:
Originally Posted by bigredscowboy View Post
I have one of the rare 2.2 with blown head gasket. Fel-pro blue mls failed after 35k. So it’s back out. I had a set of sti gaskets (11044aa642) and everything lined up. Simple google search gave me this:
https://forums.nasioc.com/forums/showthread.php?t=1713699


So this was from 2009. STI AA642 mic’ed out at 0.8mm for me, so I used it (old Felpro was also 0.8mm). Called my people at Subaru and they said the present 2.2 p/number is still 542. 2004 2.5 N/A is 632 and/or 633. He didn’t have a thickness spec. Rep said it was possible that all the gaskets are the same thickness.

So did Subaru add some thickness to the sti (642) over the last decade or was the above DOHC turbo a wrx only measurement (641 @ .58mm)?

Also, will I have any valve interference or tensioner problems if my guage was wrong and the 642 was actually 0.58mm when it needs 0.8mm (or more for the .001” I shaved off)?


I saw this post and have a question for anyone where who may have the relevant experience. I own a Subaru forester usdm ej2.5 l I swapped to a jdm ej20 and blew head gaskets on the jdm ej20 I am trying to verify whether gaskets mentioned above 110044AA483 will fit this engine I have been told that gaskets for the ej205 02-05 wrx are what fits this? Anyone have any relevant experience with this as I would like to ensure I have the right gaskets for this jdm ej20 motor
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