Subaru head gasket issues. (vs. Porsche)

This is more of a shower thought than a grave concern but Subaru flat engines have long been ridiculed for head gasket issues. Seeing that Porsche also uses a flat design and doesn't have these problems as much I was wondering is the problem more a materials issue, a basic design issue an engineering issue, or is Porsche sprinkling fairy dust from magical faeries that live deep in the black forest onto their gaskets before assembly? 

I own a Subaru and am contemplating Porsche ownership for my other car replacement late in this year. This next car I buy is the one I want to spend the next 20 to 25 years with. And that ain't gonna be the Subaru.

The Subaru issues are largely due to poor gasket design as far as I know, it has little to do with the engine being horizontally opposed. In the late 90’s Subaru went from a composite gasket (which never really had issues) to a MLS gasket with a special coating that was (unfortunately) found to deteriorate around 80-100k miles.

FWIW it helps that older Porsches don’t have any coolant to worry about, but that said, early water-cooled Porsche flat sixes have plenty of issues all their own. Just not with head gaskets.

My first thought is, is it really true that Porsche doesn’t have these problems as much? I mean, maybe they don’t, but Porsche’s require a lot of attention and are expected to. Subarus are not expected to require the same amount of attention. Maybe it’s an expectation issue. 

Frankly, I don’t like the design, in either car. 

I'd like to know as well. I've wanted but never owned a subaru because of their head gasket history. That one is a deal breaker for me as just an unacceptable repair bill. 

Considering the class action lawsuits against Subaru, I'd say it's a design flaw particular to the engine. IANAPE (I Am Not A Powertrain Engineer) however.

I thought it was basically the design of the engine block/case.  The n/a models with the HG issues have an open deck and I thought the block was not rigid enough?

Interesting, If it was as simple as a materials issue, why not change the materials and eliminate the issue. From sources that own Porsches (oh rhymey)  this is so unheard of that it never comes up but owners of subarus that religiously follow  their maintenance schedule still have head gasket issues. draws me towards an issue with either the design or engineering  or materials used for gaskets.

ProDarwin said:

I thought it was basically the design of the engine block/case.  The n/a models with the HG issues have an open deck and I thought the block was not rigid enough?

So turbo models like my XT should not have an issue?

I haven't heard of HG issues on the turbo motors.

Pretty sure the class action against Subaru is for oil consumption on the new engine (2.0 I think) that replaced the 2.5.

Having seen the 2.5 apart there is a very narrow sealing area that asks a lot of the head gasket. My local Subaguru fixed our Forester and he was of the opinion the gaskets are mostly to blame. He uses a brand calls STARS and claims they don't fail again unless the car gets overheated. He had nothing but derision for the OEM ones. I can only offer that we put about 60k miles on ours after the reseal and had no further issues.

The DOHC 2.5 is best avoided as they will intermix coolant in the oil. The SOHC ones typically just start by leaking oil externally and give you a window to deal with them before any disaster.

Most all of them will be on their second set of gaskets by now. This issue became far less common after about 2003.

When I was looking at buying my Forester with the 2.5 DOHC I asked my Subaru friends about head gaskets. Universally they told me that if it's still running there is a 99.9% chance that it's been fixed already. 

Subarus are built to a price point.  I had a Subaru, one of my friends has had 4-5 of them, all of them suffered from annoying little quality issues. 911 owners tend to overlook similar quality issues because: 911.  Neither brand is going to be the go-to for ultimate reliability.  

Early water-cooled 911s may have good headgaskets, but you have cracked heads, IMS bearings, Air-oil separators, bore scoring and d-chunking to worry about.

So, while HG issues are annoying on a Subaru, dropping a couple grand or less to fix them falls under the 'minor maintenance' cost and complexity issue on a modern Porsche.  And stuff like that is accepted as part of the Porsche experience.

I've owned and enjoyed both.  Repairs are just part of the ride.

mazdeuce - Seth said:

When I was looking at buying my Forester with the 2.5 DOHC I asked my Subaru friends about head gaskets. Universally they told me that if it's still running there is a 99.9% chance that it's been fixed already. 

Until it leaks again.  Its not a one-time fix.

HGs on the NA motors are a maintenance item.  Ask anyone who runs one competitively. 

The early 996/986 motors suffer from alphabet soup issues (RMS, IMS, Etc) but they don't suffer from head gasket issues.  Whether that's a better gasket being used or a wider landing area on the heads, I don't know.

I would dispute that 911 owners suffer through minor issues because 911.  People who buy Porsches are incredibly OCD about their cars and want them to run, perfectly, period.  Anything that's wrong gets brought to the dealer and fixed.  Yeah, by the time the cars are on their 3, 4, 5 owner that can change somewhat but for the most part, Porsches are maintained to a high level and things aren't brushed under the carpet by the owners.

That's not to say that Porsche hasn't F'ed up their designs, I'm continually blown away at the engineering issues they've had/created....

I have a good friend who is a master Subaru dealer tech and he seemed to indicate that a big failure pattern he sees involves incorrect coolant. Funny enough he just posted all this on a Facebook Subaru group the other day:

What I notice as concern is the corrosion buildup on the edge of the gasket on the block and head side that pushes the gasket or busts the seal between the surfaces. Cause by either wrong coolant, overuse service, letting the engine be covered in the same road salt all season heat after year

Wrong coolant: dexcool, borate, silicate, amine, potassium (generic long life green or yellow) clear, pink or blue European flavors, clear, orange, and yellow domestic flavored. Peak ‘global’ although compatible for top off to unknown coolant types is not appropriate to replace a volume of coolant as it is potassium based. Blue Asian formulas are a p-HOAt type, phosphated hybrid  organic acid or phosphoric acid. The old school green organic stuff can be used but change it every 2 seasons. Toyota pink can be used as it is a phosphated formula but of a higher concentration.

The ‘conditioner’ people swear by was used to address external coolant leaks but usually you get external oil leaks instead to where this block sealer is ineffective, and does not work to prevent or treat an internal gasket failure. That is old news, ca 2002 tsb. Since then superseded by revises torque pattern, improved gasket design (770) and the requirement of blue coolant (phosphated HOAt) from 2008. The ‘conditioner’ doesn’t apply by current standards and revisions.

Thinking about it, a Porsche owner is likely to use only Porsche-spec coolant. A Subaru owner is likely to just use whatever since, hey, it’s only a Subaru!

There's a bit of misinformation in this thread, a lot of the newer (2000 on) EJ motors (turbo or na) are open deck blocks. The open deck does not help with head gasket longevity but the biggest difference between a turbo car and an NA one is the gasket itself. Turbo cars use MLS gaskets and they tend to not fail (at least if left stock or before something else lol), NA cars use a single layer gasket and the coatings fail over time as the open deck block and head move slightly against each other (from what I've read). If you are doing head gaskets on an EJ251 or EJ253 use a quality MLS gasket and you should be good to go (I've had good luck with Felpro, others use OEM turbo gaskets). My knowledge on the subject is limited to the SOHC as that is what I have personally.

I don't doubt tech's observations either on the coolant issues, I should really change mine...

Adam

The guys from Cometic Gaskets will be on GRM LIVE! this coming Wednesday.  (9pm on the GRM Facebook feed and YouTube channel)    I'd be willing to bet these guys have forgotten more about gasket design and manufacture than I'll ever know.

Cometic Gaskets

If you guys have any gasket questions, be sure to tune in and ask questions.  I'm sure it will be an interesting show.  

These guys:

pointofdeparture said:

I have a good friend who is a master Subaru dealer tech and he seemed to indicate that a big failure pattern he sees involves incorrect coolant. Funny enough he just posted all this on a Facebook Subaru group the other day:

Thinking about it, a Porsche owner is likely to use only Porsche-spec coolant. A Subaru owner is likely to just use whatever since, hey, it’s only a Subaru!

This. There are probably a lot more Subarus getting driven by owners who want a low buck appliance and skimp on maintenance. Given that there are just probably more Subarus out there, so more will fail and more people will talk about it is also a factor. 

ProDarwin said:

I haven't heard of HG issues on the turbo motors.

Nope they just have ringland failures and oil consumption issues. Don't forget throwout bearings failing at 10k miles on 2015+ WRXs either. Or plastic turbo intake tubes being faulty (recall issued however). 

In reply to DirtyBird222 :

Or the oil pick up tubes cracking off.  Or the E36 M3e tunes from the factory that run the motor lean.  Or....

I’ve owned several ac 911s,  currently have three including a turbo,  and have never had a head gasket issue.  I did have a Toyota 22re that went through three however,  all in under 200k miles.  Never owned a Subaru, so no direct experience there.

In reply to Cotton :

I hope you don't have head gasket issues with an Air Cooled 911. 

I've replaced head gaskets twice on Subarus. My current Forester is also on it's third set; the original pair, an oem replacement set installed at around 100k miles (before I owned the car), and I just replaced them again at 200k miles with felpro MLS gaskets. My hope is that the felpro gaskets will last the remainder of the engine's life. The Subaru gaskets were definitely crap. When you take the heads off you can see where the black coating has deteriorated and eroded away from the base metal. There often appears to be rubbing marks on the gasket, probably from movement between the heads or block relative to the gasket. My understanding is that a good set of gaskets and regular coolant changes will actually fix the problem. 

Also the smell that comes from the headbolts when they're removed is one of the most pungent smells I've experienced from a car.

DirtyBird222 said:

ProDarwin said:

I haven't heard of HG issues on the turbo motors.

Nope they just have ringland failures and oil consumption issues. Don't forget throwout bearings failing at 10k miles on 2015+ WRXs either. Or plastic turbo intake tubes being faulty (recall issued however). 

2.0s don't have any of those issues

Also the smell that comes from the headbolts when they're removed is one of the most pungent smells I've experienced from a car.

The oil in those headbolt holes only gets changed once every headgasket. So depending on how you look at it that's either not often or way too often.