Headgaskets - 4 cylinder verses 6 cylinder - Subaru Outback - Subaru Outback Forums
 
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post #1 of 3 (permalink) Old 01-12-2010, 02:46 AM Thread Starter
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Headgaskets - 4 cylinder verses 6 cylinder

I'm just curious...why is the 4 cylinder engine prone to head gasket failures, but the 6 cylinder engine isn't?

Chris
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post #2 of 3 (permalink) Old 01-12-2010, 09:44 AM
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Re: Headgaskets - 4 cylinder verses 6 cylinder

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Originally posted by Daboo
I'm just curious...why is the 4 cylinder engine prone to head gasket failures, but the 6 cylinder engine isn't?

Chris
Subaru used a marginal design for the head-block interface, then used a marginal head gasket.

It's the kind of thing that only shows up after a few million cars have been sold, though.

The 6 may be not prone to the problem just because the holes for the cylinders are smaller- not sure if the basic design is the same, or if the 6 has more bolts or a wider sealing surface,etc.


Dave
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post #3 of 3 (permalink) Old 01-13-2010, 08:12 PM
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These are a couple of great articles that deal with the design of the block, heads, and gasket for the H4 (for 1996-1999 models) which illustrates the problem. It doesn't compare to the H6, but I believe Dave is right in that you are deal with mating surface that is more conducive to HG survival in the H6.

http://allwheeldriveauto.com/subaru-...ems-explained/

http://allwheeldriveauto.com/a-bette...et-in-seattle/

BTW: I am moving this thread to the HG Forum under problems and maintenance.

I'm not retarded, I just don't proofread my posts
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