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Second time around for head gaskets, recommendations?

19K views 38 replies 9 participants last post by  Unibody62 
#1 ·
I’m pretty sure my head gaskets are starting to fail again on my 08 Outback 2.5i. The first time was around 99,000 miles, currently have 168,000. I was checking out parts on Rockauto.com, and wondered about the quality of head gasket sets. I know that Felpro are supposed to be good, but that’s what I used the last time. Anyone had experience with Enginetech brand? The set is less than half the price of Felpro. They also have headbolts, which I think I may replace this time. I’m not going to risk it if there is any question, saving lots of money doing it myself anyway. Also wondering if I should consider doing a valve job this time around. The car still runs great and doesn’t seem to exhibit signs of valve wear. It doesn’t even use excessive amounts of oil.
 
#2 ·
No knowledge of Engintech brand. I'd use Felpro, Six Star, or Subaru XT multi-layer only. When I did my 2008 2.5i NA at 104k, I had the shop use Six Star.

Did you resurface the heads when they were replaced at 99k?

No oil consumption at 168k is very good, BTW. I'm at 134k on mine at the moment, and it's slowly increasing usage, perhaps a quart in 2k miles.
 
#5 ·
No knowledge of Engintech brand. I'd use Felpro, Six Star, or Subaru XT multi-layer only. When I did my 2008 2.5i NA at 104k, I had the shop use Six Star.

Did you resurface the heads when they were replaced at 99k?

No oil consumption at 168k is very good, BTW. I'm at 134k on mine at the moment, and it's slowly increasing usage, perhaps a quart in 2k miles.
It does use some oil, maybe 1 quart between oil changes, but I’ve always used Amsoil synthetic oil with yearly drain intervals. The past few years I switched to semi annual drain intervals, probably 8000 miles between changes. I did that because I was adding 2 quarts or more on the yearly schedule. When I switched to semi annual, I stepped down to their OE series oil, which is still rated to go up to 10k.
 
#3 ·
1. Use Subaru gaskets....Fel Pro and Cometic are additional options but they're not necessary, significantly cheaper, or better, and muddy the water. Six Star is just a rebranded Cometic gasket. Cometic is the go to source if you need different thicknesses for a custom situation.

2. Reuse the headbolts if they're original. clean the threads in the block and the bolts and properly lubricate the bolt threads.

If the headbolts were replaced last time - I'd get Subaru bolts when doing it the second time - either new or used and clean them. I've seen repeat failures of engines with Fel-Pro replaced headbolts....maybe an outlier, labor mistake, or possibly a false sense of security with poor choice of focus on bolt replacement, but it's pointless except you get to avoid cleaning the old threads. I would only use Subaru bolts given Fel Pro makes the erroneous claim to replace headbolts without any proper qualification regarding the Subaru design engineers who say not to replace them. if you're going to go against the design engineers on a problematic area, please describe in statistically meaningful terms why.

3. resurface the heads and adjust the valves. they don't need checked or full valve job, waste of time.

You don't need an entire kit, you only need: Subaru headgaskets, intake manifold gaskets, and exhaust manifold gaskets. Coolant cross over orings and valve cover gaskets are a good choice while you're in there. Nothing else ever really fails or is problematic.
 
#4 ·
That’s all really helpful info. I just bought gaskets (not the complete set) I needed the first time, but was also doing the timing belt/water pump. I reused the original head bolts the first time, just didn’t know if I should push my luck again. I didn’t resurface heads, but I checked them for flatness and warp. I might take to a machine shop and have them resurfaced. I don’t think I’ll do a timing belt right now either, it’s not all that hard to do later. Who knows if I will keep the car for another 30k miles anyways.
 
#7 ·
Are you aware that properly GROUNDING the heads (electrically) is imperitive to a long-lasting head-gasket job? If not grounded, all the high-voltage from the ignition system is forced to arc thru the head-gaskets to complete the circuit. (do not assume the headbolt threads will make solid electrical contact.)

Some mechanics do not reinstall the factory head-ground straps after replacing gaskets.
 
#8 ·
I did reattach the ground straps. I would concede that maybe the heads were not machined the first time (as @aesthetic.rake suggested ) may be the cause of failure. I was ,of course, trying to save a few bucks and didn’t want to needlessly pay for resurfacing. But I almost think that there is no getting around doing it every 100k or so.
 
#11 ·
#12 ·
I concur with grounding.
If the HGs are failing due to oil leakage, then my question is was MLS gaskets used?
If the HGs are failing due to coolant consumption, then there may be another issue with temperature control.

If it's oil, check this out: https://www.subaruoutback.org/threads/ej-head-gasket-leak-experiment.512591/
Mine is primarily coolant seepage. It is just starting to get the telltale smell when I shut it off. I used Felpro gaskets. I doubt there is any lack of good grounding, but I will verify when I get ready to work on it. I have a PowerProbe that will tell if if the ground is good. It does not overheat or even run hot, the radiator was replaced sometime after the head gasket was done and I’ve never added anymore coolant since then. Just thinking it’s the nature of the beast. All in all, very low maintenance on this car.
 
#15 ·
Subaru isn't the only one with weak gaskets. Every Ford/Mazda 4 cylinder tends to blow the head gasket without warning as early as 120k miles. When it starts weeping, you don't notice it, then one day you go out to start the car and it's blowing white smoke. I've seen it plenty. Reason: single layer gasket with graphite blend on both sides.

Granted, a HG should not be a maintenance item, but when it's a know issue, it becomes one at least the first time around so it can be replaced with an improved gasket.

Manufacturers may not put a HG in their maintenance schedule, but they also defer from putting transmission fluid on it as well. Research your cars and learn about them.
 
#16 ·
Everyone touts the MLS gasket as being the savior of the sohc ej25 because the turbo'd, dohc ej25 isn't prone to headgasket failures and the obvious difference is the MLS gasket. For whatever reason, the extra, outer cylinder wall supports cast into the block of the ej255/7 get ignored. These supports severely cut down on vibration/cylinder wall movement/flex, which in turn, cut down on head gasket "wear."

Since I've had the unfortunate experience of tearing the top end off a sohc ej25 that recieved a fresh set of SixStar gaskets nearly immediately after the engine was installed, I can attest that a part of the design of the "improved" gaskets is to (IMO) attempt to mechanically lock the top of the cylinder wall/face of the block to the head. There's a thicker ring inside the improved gaskets that doesn't compress like the rest of the MLS gasket. This ring I believe is intended to indent itself into the head/block to try and prevent this vibration or movement.

I ended up tearing apart the engine I mentioned above due to an air pocket that I mistook for a blown head gasket (coolant violently erupting out of the radiator.) Pulling the heads back off and taking them down to be milled again, the machinist pointed out the "dent" caused by this ring and this has had me thinking about it for the last year and a half or so since then.

The other day, this guy posted this on Youtube. He's deliberately milling a groove into the surface of the block and installing a copper wire to put more pressure, and a harder material, against the head gasket/head in that area and it got me wondering if what I saw on the engine I mistakenly tore back apart was what was actually going on.
 
#17 ·
I ended up tearing apart the engine I mentioned above due to an air pocket that I mistook for a blown head gasket (coolant violently erupting out of the radiator.)
Yes, I almost made that mistake last time, but fortunately, I checked further before I tore it down. Interesting video, if I were building a performance ej25, that might be something to consider, but not for everyday driving.
 
#20 ·
Not sure about the experience of others but the head gasket failures I have seen on the EJ25 SOHC motors have never involved the compression area of the cylinder. The ones I have seen have always involved either the water jacket leaking to the outside of the engine and/or the oil galleries leaking to the outside of the engine.

This is why texting for combustion gases in the coolant is not a good test for failed head gaskets in EJ25 engines.

I am aware that some people report a failure in the combustion chamber part of the head gasket but I have never seen one myself, maybe because I choose to replace the head gaskets when there are signs of coolant or oil leaking.

Seagrass
 
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#21 ·
Maybe, but it seems quite logical to me that the coolant and oil are being forced out because of combustion chamber leaks. I just read a post on the forum the other day where the OP complained of foaming oil as well as oil leakage.
 
#23 ·
The oil issue is due to the vibration as mentioned but also because the material on the SLS gasket from the factory is eaten through by the corrosives in oil. Old cars were put together with cork mix gaskets that would allow oil to seep out and eventually crack due to the heat from the block and head over time. At this point the oil leak accelerates. It's the same with the blend on SLS gaskets.

Use of various blended materials has improved component sealing and the longevity of the gasket. But the HG remains a weak spot even though it's believed that the gasket is a "forever gasket". It's not and neither is any other gasket on the engine. Even GM blocks have seeping HGs by 100k miles and I'm referring to V6 and V8 engines. It's not a Subaru thing, it's an all manufacturers thing. It's physics and mathematics. You'll not escape from it, you can only do what is known to improve the situation and increase the life of the engine.

At least it's not a Bimmer. When owners slack on maintenance, oil leaks start and they don't stop until you've changed every gasket on the car. Because you fix one leak and the next weakest leak gets heavier. And when one of these has a gasket leak, the engine runs like shite. MB is the same way. VW, Audi, Porsche; an oil leak is a vacuum leak.
 
#24 ·
Re: adjusting the valves. After I get the heads resurfaced, can I adjust the valves off the car? The shop manual assumes the heads are installed, but one need only to make sure there is no load on the springs, so I don’t see why you couldn't do it before you install. I am thinkng it would be much easier if I end up not pulling the engine.
 
#25 ·
You will want to pull the engine. It makes things soooo much easier, especially torquing the head bolts. Those last 3 turns on the bolts, (1 90° and 1 45° on all 6, then the last 45° on the center 2), can be a PITA with the engine in. Having the engine out also makes valve adjustment easier because you can rotate the engine easily and you can see the gauge better. Engine in means jacking up one side at a time and unless you get the engine braced up solid, when you go to torque the heads it may move on you. Just sayin', sometimes the long way is easiest and more productive.
 
#26 ·
Thanks for the input, sounds like you may have done both ways. I have a 4 post lift, but no cherry picker. I borrowed one before, so I would have borrow again. Not having the best back in the world, I’m leaning towards pulling it again, but I’ll likely want some help dropping it back in there in order to get everything lined up. That’s kind of why I was thinking about doing the job without yanking it. I’ve watched YouTube vids where they shifted the engine side to side to give more clearance when doing the head bolts. Like I said, I don’t think my back would be happy with me if I went that route.
 
#29 ·
I work on these engines a lot.

To get the lower 14mm nuts off, with the car hanging, pop the CV axles out or the front diff. This will give you clearance to get a socket on the nut. When you have everything together, make sure you hear that joint snap on the stub shaft before you try to drive it.

Auto trans cars, pull the intake to make it easier to get to the torque converter bolts. You have a straight shot to them. On manuals, pull the engine with the intake on it.

Clean every area that uses a gasket prior to assembly. Roloc disc, medium #07481 works great on the heads, block, intake and exhaust ports.

besides having a torque wrench, have a 3' breaker bar handy for breaking the head bolts loose and getting those final turns on assembly.

MLS gasket 11044AA770 is the Subaru part number. It's an HG for the EJ255. Fits perfect and seals great.

It's been my experience that Fel Pro gaskets don't fit proper.
 
#30 ·
I work on these engines a lot.

To get the lower 14mm nuts off, with the car hanging, pop the CV axles out or the front diff. This will give you clearance to get a socket on the nut. When you have everything together, make sure you hear that joint snap on the stub shaft before you try to drive it.

Auto trans cars, pull the intake to make it easier to get to the torque converter bolts. You have a straight shot to them. On manuals, pull the engine with the intake on it.

Clean every area that uses a gasket prior to assembly. Roloc disc, medium #07481 works great on the heads, block, intake and exhaust ports.

besides having a torque wrench, have a 3' breaker bar handy for breaking the head bolts loose and getting those final turns on assembly.

MLS gasket 11044AA770 is the Subaru part number. It's an HG for the EJ255. Fits perfect and seals great.

It's been my experience that Fel Pro gaskets don't fit proper.
Big help with all your advise. Will the axle pop out without removing other suspension parts, like ball joints or control arm? I believe I just left the axles and auto tranny all intact last time. I just used a razor blade and scraped the surfaces before. I didn’t use a tool where I could dig into the surface, but just used to edge in kind of a brushing motion, no chance of gouging. I think I read that using a scuff tool such as roloc could cause problems with the surface.
 
#31 ·
Yes on the axles. You just pry them out of the diff. They will not come off the stub shaft but will move out of the way enough to get the tranny nuts. It also gives you more flex when you lift the engine/trans to separate them so you don't separate the CV joint.

I use roloc all the time. They are made for aluminum surface cleaning. You can get a finer roloc than medium if you want. The problem with using them is that if you use too much pressure or scuff one area too long you will leave a gouge or low spot in the surface. Light pressure to remove gasket material and shine up the surface a little. Use a variable speed drill or die grinder that can utilize the roloc adapter and run a slow speed. There is actually less chance of gouging the surface with a roloc than with a blade.
 
#32 · (Edited)
You'll have to pull the suspension apart to get the axle out. Either by separating the knuckle from the strut or the ball joint from the lower control arm.

Better, and easier, to pick up a set of these to get that lower nut off. The $30 you'll spend on the flexible sockets will save you hours of work, and, if you forget to mark the bolts, an alignment as well.
 
#33 ·
No way that I would take apart the suspension to do this. I don’t remember having a big issue unbolting everything 5 years ago. Besides @cardoc just stated that it was not necessary. Sounds like you need the weight off the tires do accomplish the axle release, though.
 
#34 ·
I've never had any luck getting enough lateral play in the axles to be able to get a decent, straight socket, even with a wobble extension on the lower two nuts of the bell housing. Everyone's mileage will vary but here in California I don't have much issue pulling apart the suspension--not that it's hard in the first place.

Of course, all doing all that nonsense was prior to buying those swivel sockets. Now I don't have to pull **** apart or even mess at all with the axles. It has literally become a non-issue and I completely forget about that lower nut even being at all problematic until someone on here brings it up.
 
#37 ·
I neglected to post the outcome of my whole debacle, for any who were following. I was all prepped to pull the engine and do the repair, but when I took off the belly cover, I saw that the head gaskets really appeared to be intact and not leaking. I was getting some minor oil leaks from other places and making it’s way to the oil pan, (but not enough to drop on the garage floor) and also coolant leakage, so I just jumped to the conclusion it was HG again. The thermostat housing was the source of my antifreeze leak, and I recall that the housing was less than perfect at the 99,000 mark, but it seemed to clean up good enough. Don’t know if the gasket failed (since it was a non-Subaru part) or what. Anyway, I decided to go ahead and do the timing set, water pump, bought a new housing cover, and it’s all good now. Spark plugs were replaced as well, as the old ones were pretty well shot. I think they had about 90kmiles on them and the gap was way too wide at this point. The moral of the story, do your homework and verify before jumping in. Glad that it’s all behind me now and I avoided the extra work of an power plant removal. ? Thanks for all the advice, everyone. I learn new tricks and things all the time.
 
#38 ·
Glad that you dodged a bullet there.

And I hear you on the part about doing your homework and verifying before jumping in. I have to continually remind myself to have an open mind when doing diagnosis and not expect any preordained outcome based on my previous experiences - or the collective previous experiences of this forum. We expect head gaskets to fail, after all, so we focus our diagnostics on the oil leaks, antifreeze loss, and other signs, ignoring all other symptoms.

In this case, it was a happy outcome, and you got caught up on some other necessary maintenance - congratulations!
 
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