[Subivince]

Hi all,

Just completed the removal of the cylinder heads from the wife's 01 outback, sent the heads off to have them checked for flatness. I'm using the six star gaskets for this job, wondering A) if anyone has experience with them? and B) if they are especially sensitive to head / block flatness?

If you have done this DIY, would love to hear from you.

Thanks in advance

 

[Subivince]

Never mind on the first question just found many many threads on this I'm good with the six star. Tried search on this forum but they came up when I did a google search. Go figure.......

Still interested to see if many of you have had problems with heads warping?

 

[AWDFTW]

If the vehicle overheated, then yes there is a decent chance of warping.

 

[radio head]

I don't really see any reason to not have the heads machined. Think of how many heating and cooling cycles the heads (and the whole engine) have gone through...

 

[Subivince]

Yup that's true. I agree with you about the common sense of getting them milled. Just wondering if warping is a common problem with these short heads.

 

[ntippet]

Used these six star gaskets when I changed my headgaskets.
Preventative maintenance since there was a bad oil leak starting, the engine never overheated.
When I measured flatness the drivers side lower rear oil return passage showed .02".
Had the heads machined.
From the number of engines showing oil leaks on the drivers side in this exact area, I can only suspect a factory machining or assembly error.
That coupled with the less than stellar headgaskets these SOHC engines received, its no wonder this generation has such a high failure rate.
Haven't had a problem since, not even a trace of any coolant or oil.
I push this engine very hard so I don't expect any more problems.

Get the six star or the turbocharged factory MLS headgasket.

 

[subiesailor]

Yup that's true. I agree with you about the common sense of getting them milled. Just wondering if warping is a common problem with these short heads.

No actually the opposite the short compact heads are much more resistant to warping than your standard inline head which almost always warps when things are not exactly correct.

All the Subaru shops that do HG work pretty much say the same thing the surface prep on the head is crucial to the HG job and it is a very rare case to see a warped head. The primary cause for a warped head on the Subaru would be cooking the engine due to some type of failure and continuing to drive it till it shuts down on its own. Which case the heads may be warped and there may be other internal damage to bearings and such which at that point a HG job might correct the HG issue but a bearing failure soon after due to damage caused by extreme heat will more or less finish the engine.

The head gasket most folks suggest are the OEM turbo gaskets which are heavier constructed and have the proper updates and are not known for having failures like the non turbo gaskets used in the 2000-2003's

 

[Caboobaroo]

I use them all the time:29:

Typically, from what I've seen, the models of SOHC with EGR are warped more often and worse then ones without EGR. Probably due to the exhaust cooling as it passes through the EGR piping but that's just speculation.

If it hasn't been overheated, they probably aren't warped too badly but the Six Star gaskets recommend the heads under 0.002" warp which isn't much. If you don't have an accurate way of measuring, probably be safer to have them machined. Then you have a clean surface to work with as it can take awhile for some of the imperfections in the head surface to sand out.

 

[idosubaru]

have them resurfaced. i'm not sure what the definition technically speaking of "warped" is, but it doesn't matter. there are always high and low spots on the head surfaces, even if they weren't overheated, that you see when resurface them. not sure if that technically means they're warped, but i would always resurface these heads.