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Old 01-12-2010, 01:46 AM   #1 (permalink)
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Default 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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Old 01-12-2010, 08:44 AM   #2 (permalink)
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Default Re: Headgaskets - 4 cylinder verses 6 cylinder

Quote:
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.


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Old 01-13-2010, 07:12 PM   #3 (permalink)
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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.
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