Need help selecting the right OB / engine

[softroader]

New to Subaru and these forums.  I'm looking for a Gen 2 or Gen 3 OB to be used for softroading and camping but having trouble figuring out which combination of OB, engine and transmission will best suit my needs, and which engines to avoid.  I've been wrenching on cars for a long time so I don't mind doing things like replacing the TB, head gaskets, or buying a rebuilt Subaru short block and putting heads on it etc.

After hours reading and searching these and other Subaru forums I'm getting a bit lost in all the information, largely because I'm not clear on exactly which engines were used in which model years even after looking at cars101.com and the Subaru engine wikipedia pages.  Many of the posts here have been very helpful, especially those by GeneralDisorder and the other gurus, but I still have questions that I'm hoping the experts here will respond to:

• I have a strong preference for the MT, which unfortunately pretty much rules out the EZ30 engines for me.  I like the EZ30 engines because I prefer timing chains and they don't seem to have the same head gasket problems as the EJ25.  Not sure I could live with an AT to get the EZ30 but maybe.
• GeneralDisorder posted somewhere here (sorry, I'm not sure how to quote a post from another thread) about the 2005+ OBs being in "CANBUS h*ll", a view I strongly agree with.  Too many fragile and nonessential things on the CANBUS that can fail and kill it, disabling the vehicle. Not a good thing miles from paved roads.  So I think that rules out the Gen 3 2005-2009 OBs for me.  Good news there is I won't have to deal with expensive immobilizers either.
• GeneralDisorder posted about EJ25 family engines that have 7-9mm oil pumps and are even more prone to rod bearing failure caused by increasing main bearing clearances due to soft case aluminum alloy.  Exactly which engines are these, and what year OBs were they installed in?  Are these the EJ251 engines in the 2000-2004 OBs?  The ones with a worse head gasket problem than the 2005-2009 OB engines?

If my understanding is correct (not likely at this point) it looks like my choices might boil down to these:

• A 2001-2004 OB with the EZ30 6-cyl engine and 4AT.  Good: timing chain, head gaskets, JDM EZ30s are cheap and available, more torque, AT better at slow speeds off pavement than a MT, can mod a 4WD switch. Bad: I want a MT, an AT has much more to break than the MT.
• A 2001-2004 OB with EJ25(?) 4-cyl engine and 5MT. Good: 5MT.  Bad: timing belt (not so bad), head gaskets, rod bearing failures (is this the engine with the feeble oil pump?)  Confused about exactly which EJ25 version was used in this OB.
• A 2005-2009 OB with EJ253(?) and 5MT.  Good: better engine 2006+ (175hp, variable valves). Bad: CANBUS h*ll, expensive immobilizers.

I know that's a lot of muddled and probably not quite right information.  Can someone please help me sort it out?  Thanks in advance.

[1 Lucky Texan]

everything I have read points to the 4EAT being much superior off-road to the 5spd.

just  my opinion(also, my WRX's 5spd removed all the teeth from 2nd gear - under 70K miles, NO power mods)

[softroader]

3 minutes ago, 1 Lucky Texan said:

everything I have read points to the 4EAT being much superior off-road to the 5spd.just  my opinion(also, my WRX's 5spd removed all the teeth from 2nd gear - under 70K miles, NO power mods)

Of course it's a matter of individual preference, but would you say it's worth giving up MT fun for the advantages of an AT off-road?  I'm really torn on this, I have been driving a 5-speed MT for years and years and love it (and will keep it when I get the Subie), but there's no doubt that an AT is better off-road especially at slow speeds and around obstacles, a MT clutch won't live too long under those conditions.

Before you bought your 03H6OBW did you drive a 4-cyl MT OB?  Impressions?  Are you still glad you got the H6 AT?  I'm leaning toward the H6, I like the timing chain, fewer head gasket failures, more power and torque, etc.  Just wish they had offered a MT with it in Gen 2 OBs (retrofitting one is more headache than I'm willing to take on, especially with California smog testing).

[1 Lucky Texan]

one or 2 people have swapped-in a 5spd or, better, a Legacy Spec B 6spd into an H6. the H6's xtra power would probably be a death knell for the 5spd.

If you're just on flat-ish/dry-ish gravel/dirt, 5spd 4cyl probably OK.

others here will have actual off-road experience for your questions. I mostly wanted to warn you about 5spds - they have a but of a poor reputation. Certainly more-so among WRX owners - they start tuning the car and then complain when the clutch or trans fails.

I paid $2000 to fix my trans(2nd gear is cut onto the main shaft w'ever), wish I could have afforded to just get a 6spd put in but, alas, I couldn't justify it at the time, plus all the other internals looked great (the tech said) and - under 70k miles too.

Edited October 14, 2020 by 1 Lucky Texan

[softroader]

3 minutes ago, 1 Lucky Texan said:

[...] I mostly wanted to warn you about 5spds - they have a but of a poor reputation. Certainly more-so among WRX owners - they start tuning the car and then complain when the clutch or trans fails.

I paid $2000 to fix my trans(2nd gear is cut onto the main shaft w'ever), wish I could have afforded to just get a 6spd put in but, alas, I couldn't justify it at the time, plus all the other internals looked great (the tech said) and - under 70k miles too.

This is exactly why I'm having trouble deciding which 2000-2004 Outback to get.  One moment I'm leaning toward the H6 with AT because of the extra torque and advantages of the AT off-road, then I come across a post (here, I think) that says that usually when the Outback AT fails it's so expensive to replace that people usually just give up on the car.  So back to the EJ25 with 5MT, simpler and more robust than the AT, no worries about the AT failing, just timing belts (I've come to terms with that, easy to replace and no big deal), and head gasket problems (I can do that myself, and lost of good info around).  So, leaning toward the 5MT.  Then I read your post... the MT decided to puke up all its 2nd gear teeth on an unmodified vehicle?  AYFKM?  Why is it so hard for Subaru to properly engineer their vehicles?  So now I'm just bouncing back and forth between the H4 and H6, trying to decide which money pit of problems would be better.

[Numbchux]

AFAIK, all EJ251/EJ253 SOHC non turbo 2.5s have the 7mm pump. But, a WRX 10mm pump is a direct replacement for about $150. Simple during a timing belt job.

Good used transmissions are very reasonable. Even for my VDC, I could get one for less than $1k. That's not enough to scrap a car, IMHO. Rebuilding a transmission is rarely worth the cost. But most of these cars that are in the junkyards are there for other reasons, so there are plenty of good used transmissions.

These cars are fantastically engineered. But they're approaching 20 years old, nothing is exempt from issues, and at this age they either have a lot of miles, or a lot of sitting (and usually neglect), neither is great for a car. Some things are more likely to wear out, but I wouldn't call any of it a problem, per se.

 

 

I currently own 6 BH (00-04 Wagon) Outbacks. 4 are H6s, 3 of those are VDCs, one of the H4s is a MT, only one has less than 200k miles. They all have their advantages. But I definitely prefer the VDC, the VTD AWD is so much better than a standard MPT AWD in the other AT cars. And the yaw and steering sensors included with the stability control mean the ABS is far better. The stability control doesn't let you drive sideways everywhere, but that's OK with me.

My '00 H4 5MT has 335k miles, I just put an STI 11mm oil pump (a friend had a new OEM one he wasn't using, or I would have done the 10mm),  and timing set on it. Needs some suspension parts, but I don't hesitate to hop in it and drive it. I plan to drive it this winter, as I prefer the extra control afforded from the MT driving in the snow and ice (I have hundreds of hours of seat time ice racing...).

The H6s (especially the VDC models, which have more sound deadening/insulation) are so comfortable. They're faster, but you don't really notice it as they're smooth and quiet.

The 5-speeds don't hold up to WRX owners that watch Ken Block all day and then do donuts all night. But behind a non-turbo engine with an occasional fluid change, they hold up just fine. Again, used transmissions are cheap.

The H4s are plagued with piston slap, not actually anything to do with reliability, but they're rattley. H6s can have serpentine pulley bearings fail with little warning, but the bearings are about $15 each. Most H4s have had head gaskets done by now, which means they've had new valve cover gaskets, whereas the H6s probably have original ones, so they probably leak. Spark plugs kinda suck on the H6s. H4 5MT definitely don't have a oil cooler, I think the 4AT ones do. Both engines use the same cooler orings that can leak. They both use the same oil pressure switch which can leak.

 

On technical/rocky offroad trails, the automatic is FAR superior, offering far more control and finesse. On sand, I understand automatics tend to overheat, so a manual might be better (I have zero experience with this). 

 

Basically, I'd jump on a good deal on a good example of any of these without hesitation. If price and condition were no object, it would be a 2003 VDC in Forest Green, or 2004 in Black (I love the solid black look, but not a fan of the On-star and non-adjustable LH defrost vent, but those can be changed).

 

 

If I was given an 05+, I would just turn around and sell it.

[el_freddo]

The problem with the gearboxes is hard gear changes - and constantly. Many WRX gearboxes break second due to hard high rpm gear changes. Mods or not, the extra torque produced on boost isn’t nice on gearboxes due to shock loading etc. AWD traction doesn’t help either. 

The EJ251 as I mentioned in Numbchux’s “help me decidel thread, cops the poor reputation of the EJ25D and the crappy factory HG didn’t help. Swap them for MLS HGs. 

The H6 HG seems more seems more economical to swap the whole engine for an import create engine. I’ve heard issues with burning valves if valve clearances aren’t done at the service intervals. I don’t have any direct experience with this, just “heard” about it. 

The Gen3 is a solid platform. 

What sort of soft raiding are you planning to do? Either way, an auto will spoob all over a manual, more so that you don’t have a low range in the manual. 

Cheers 

Bennie

[softroader]

3 hours ago, Numbchux said:

Good used transmissions are very reasonable. [...] there are plenty of good used transmissions.

These cars are fantastically engineered. [...] but I wouldn't call any of it a problem, per se.

I currently own 6 BH (00-04 Wagon) Outbacks [...] They all have their advantages. But I definitely prefer the VDC [...]

The H6s (especially the VDC models, which have more sound deadening/insulation) are so comfortable. They're faster, but you don't really notice it as they're smooth and quiet.

The 5-speeds don't hold up to WRX owners that watch Ken Block all day and then do donuts all night. [...] Again, used transmissions are cheap. [...]

On technical/rocky offroad trails, the automatic is FAR superior, offering far more control and finesse.

Basically, I'd jump on a good deal on a good example of any of these without hesitation. [...]

If I was given an 05+, I would just turn around and sell it.

Numbchux, I can't thank you enough.  This is exactly the kind of big picture insight I was hoping for, very, very helpful to me.  I just got back from driving a craigslist 2001 EJ251 4AT with 270,000 miles, it needed work but it drove well and it was dirt cheap, didn't buy it because with an AT I want an H6.  Gave me a new appreciation for these older Gen 2 OBs (and I'm not biased, my Toyota DD is 37 years old with 409,000 miles).

I have been overthinking this, but that's easy to do with an unfamiliar vehicle, I have a Black Belt in my DD but Subies are new to me.  For many years I have wanted a silky smooth 6-cyl car, in part because my DD sometimes vibrates so much I need a kidney belt and I have had enough vibration to last me several lifetimes... always thought that would be a V6 until I heard about the Subaru boxer engines... my intended use is light offroading (forest roads, occasional bumpier stuff) while exploring and dispersed camping off pavement... Sierra Nevada, Colorado Rockies, maybe up into Canada... lots of freeway miles where noise and comfort makes all the difference over many hours.  So the H6 appeals strongly.  Though when my friend gave me a ride one time in her H4 I couldn't believe it wasn't a V6 it was so smooth.  I'm an MT guy but I'm thinking it wouldn't hurt to consider a 4AT for the softroading part, especially considering that when I go on an exploring roadtrip in the current MT DD I shift into 5th and stay there for hours on the freeway anyway.  The posts about a failed AT meaning the end of the car kinda ruined that, but you have turned that around with your post about the availability of good used ATs.

And I agree about the 2005+ CANbus cars.  As a network engineer, this is like depending on an eggshell to keep the car running.  Too many essential functions depending on a single point of failure.

[softroader]

2 hours ago, el_freddo said:

The problem with the gearboxes is hard gear changes - and constantly. Many WRX gearboxes break second due to hard high rpm gear changes. Mods or not, the extra torque produced on boost isn’t nice on gearboxes due to shock loading etc. AWD traction doesn’t help either. 

The EJ251 as I mentioned in Numbchux’s “help me decidel thread, cops the poor reputation of the EJ25D and the crappy factory HG didn’t help. Swap them for MLS HGs. 

The H6 HG seems more seems more economical to swap the whole engine for an import create engine. I’ve heard issues with burning valves if valve clearances aren’t done at the service intervals. I don’t have any direct experience with this, just “heard” about it.

Thanks Bennie.  I think the poster who described his MT puking 2nd gear teeth wasn't driving it that way, and it does sound like an exception and not typical.  Maybe it was abused before and had stress cracks or something.  And Numbchux just described tha ready availability of good used 5MTs, so I'm not worried.  I have two spare 5MTs for my 37 year old Toyota DD, same idea.

So the EJ251 inherited the bad reputation of the EJ25D?  That is reassuring.  Head gasket replacement doesn't look too difficult.

JDM EZ30 H6 engines are readily available, they run about $1100 around here, maybe $1200 delivered.  If I end up with a 2000-2004 H6 4AT Outback, I will probably just buy a JDM engine while they are available, compression check and borescope it, and store it for possible future use.  Maybe try to find a good used 4AT also.  Then if one fails, I have one.  I intend to keep my Outback for a long time and don't want to worry about the supply of major components drying up (been there, done that).

[softroader]

4 hours ago, Numbchux said:

I currently own 6 BH (00-04 Wagon) Outbacks. 4 are H6s, 3 of those are VDCs, [...]. They all have their advantages. But I definitely prefer the VDC, the VTD AWD is so much better than a standard MPT AWD in the other AT cars.

Good info.  Do you worry about the added complexity of the VDT system with all those extra sensors?  I'm looking for reliability, especially when off-road.  Is this something to worry about?  It sounds useful but is it prohibitively expensive and difficult to repair when it fails?

Off topic rant: I look at all the complex features on the new 2020 vehicles (not just Subaru) and shake my head, so many are just crutches for incompetent/complacent drivers, and cost a fortune to fix.  Lane keeping assist?  Seriously?  If you can't do that yourself you shouldn't be behind the wheel.  Maybe put your phone down and pay attention to the road while you're driving... old school, I know, but it works.

[1197sts]

FYI, the 2000 & 2001 Outbacks have 9mm oil pumps, I think from 2002 and on they had 7mm pump. There may be some exceptions, not sure.

 

[1197sts]

Forgot to specify, I was referring to the EJ251 H4.

[softroader]

3 minutes ago, 1197sts said:

FYI, the 2000 & 2001 Outbacks have 9mm oil pumps, I think from 2002 and on they had 7mm pump. There may be some exceptions, not sure.

 

Can the 10mm or 11mm oil pump be installed on all of these?  Sounds like a good way to compensate for the reduced rod bearing oil flow that GD describes.  Cheap insurance for $110.

[1197sts]

Yes, they are interchangeable. The 10 mm would be my choice, 11 is probably overkill, I think I saw GD make that recommendation as well. 

[softroader]

3 minutes ago, 1197sts said:

Yes, they are interchangeable. The 10 mm would be my choice, 11 is probably overkill, I think I saw GD make that recommendation as well. 

Sorry if this is a dumb question.  Does the 10mm refer to the thickness of the drive gear inside the oil pump?  Is the thickness of the housing the same in all of these?  If not, do other parts needs to be changed?  I have been running the same (similar to the EJ25) oil pump on my 22RE for 409,000 miles with good pressure, they don't seem to wear much at all.  Wondering why Subaru didn't just start out with a 10mm pump and stick with it...

[el_freddo]

Subaru did start out with a 10mm pump. As oils thinned out so did the thickness of the oil pump rotor. 

No change to housing that will interfere with anything else. If it’s EJ it will bolt on to any EJ block. 

4 hours ago, softroader said:

Off topic rant: I look at all the complex features on the new 2020 vehicles (not just Subaru) and shake my head, so many are just crutches for incompetent/complacent drivers, and cost a fortune to fix.  Lane keeping assist?  Seriously?  If you can't do that yourself you shouldn't be behind the wheel.  Maybe put your phone down and pay attention to the road while you're driving... old school, I know, but it works

Totally agree. More safety gear makes ppl more complacent. Look what happened to that dude in Cali that died in his automated Tesla. He was meant to be watching/monitoring - alas he paid the ultimate price for not watching. 

Cheers 

Bennie

[idosubaru]

can you take the mental ego or “gas mileage” hit, whatever it is you love about MTs when going to an AT?

once you’re over that hump relax and get an automatic.  If moving a 4” stick around is a necessity then you’re at least easily entertained. The automatics are far superior. 

offroading, loading trailers, reliability, drinking coffee.  popping the clutch to jump start an MY is the only advantage to an MT. With the availability of tiny portable power packs that’s almost a nonissue.

contrary to your comments the manuals have PITA clutch wear items, synchro failures, input shaft bearing failure, less forgiving 4WD vlsd failures, are commonly replaced instead of repaired,  and they’re not easy to find which doesn’t help prices now or in the long run.

Much of that is user wear but not all of it and all 20 year old cars means buying used transmissions and repairing/replacing with equally used ones. 

You mention autos being scrapped when repair is needed - Manuals get scrapped and swapped when they fail too. No one replaces synchros and many swap instead of repair input shaft bearings.

The autos don’t fail enough to be a statistically viable concern.  As said earlier age and history are the driving variables. 

01-04 H6 were my go to car to help people get (and ive owned a few) for 10 years or more. Great cars.  Now there’s just too much rust around here to consistently recommend local purchases.

that being said EJ25 headgaskets aren’t hard to do.  Widely available, you could buy a blown one and get a short block from Subaru for $2,200 or so with 36k 3 year warranty to start with a near new engine with warranty...(cue building movie music)...in front of an MT.

I don’t know which years got which oil pumps but I doubt it’s a one year answer. probably more like Forster X got it but legacy Y did not....etc.  you could look up the part numbers on a Subaru online parts store and click “what this fits” to see years/models  

 

Edited October 15, 2020 by idosubaru

[lmdew]

Get a nice 01-04 H6 from a rust free state.  I see them from time to time in CO.

Good ones always go fast!  Have to be ready to buy.

[Numbchux]

12 hours ago, softroader said:

So the EJ251 inherited the bad reputation of the EJ25D?  That is reassuring.  Head gasket replacement doesn't look too difficult.

I wouldn't say that, the EJ251 head gaskets leak all the time. BUT, they inherited the bad reputation of head gaskets everywhere. These VERY rarely cause overheating problems and leave you stranded, 99% of them are an external oil leak. If the oil level isn't run low, this can be put off indefinitely. I had a 2003 Outback that had seeping head gaskets when I bought it, we put 40k miles on it before fixing it and selling it.

12 hours ago, softroader said:

Good info.  Do you worry about the added complexity of the VDT system with all those extra sensors?  I'm looking for reliability, especially when off-road.  Is this something to worry about?  It sounds useful but is it prohibitively expensive and difficult to repair when it fails?

No. The extra sensors are a yaw sensor and steering angle sensor, very low failure rate. And should the system go down, it still has mechanical AWD (with an open center diff, granted) to fall back on. You'll loose ABS, VDC, and VTD functions, but it won't leave you stranded.

 

10 hours ago, softroader said:

Sorry if this is a dumb question.  Does the 10mm refer to the thickness of the drive gear inside the oil pump?  Is the thickness of the housing the same in all of these?  If not, do other parts needs to be changed?  I have been running the same (similar to the EJ25) oil pump on my 22RE for 409,000 miles with good pressure, they don't seem to wear much at all.  Wondering why Subaru didn't just start out with a 10mm pump and stick with it...

Yes, it's the rotor thickness. All use the same housing. There was an aftermarket 12mm pump that had a new housing to make room for it. These all have the same fit.

[1197sts]

Regarding the choice between an auto and a MT, I agree the Auto is the best choice. it is reliable and robust, just keep clean fluid in it and change the filter on a regular basis. I had one that had 350K on it and was still going. The MT is more fun, but it no doubt more prone to failures and higher cost of maintenance. In my area it is harder to find a used MT and they are more expensive, and there are differences between model years so you have to be careful to get the right one.

[idosubaru]

14 hours ago, 1197sts said:

FYI, the 2000 & 2001 Outbacks have 9mm oil pumps, I think from 2002 and on they had 7mm pump. There may be some exceptions, not sure.

 

that's what I had in my head - the early ones had the 9 and they went smaller somewhere in the middle of the 00-04 generation. 

by this age, it should be checked in case the engine was ever replaced, which is very common. i have no idea how many EJ25 vehicles i know had the engine replaced - it's very common. when getting a used EJ25 it needs new timing gear due to being an interference engine and the oil pump might as well be resealed while it's apart, so it's basically zero effort to check it or replace it.  have a 9mm on hand and return it if you don't need it. 

[softroader]

On 10/15/2020 at 3:23 AM, idosubaru said:

can you take the mental ego or “gas mileage” hit, whatever it is you love about MTs when going to an AT?  once you’re over that hump relax and get an automatic. [...] The automatics are far superior. [...] the manuals have PITA clutch wear items, synchro failures, input shaft bearing failure [...]

01-04 H6 were my go to car [...] for 10 years or more. Great cars.  Now there’s just too much rust around here to consistently recommend local purchases.

that being said EJ25 headgaskets aren’t hard to do.  Widely available, you could buy a blown one and get a short block from Subaru for $2,200 or so with 36k 3 year warranty to start with a near new engine with warranty...(cue building movie music)...in front of an MT.

Thanks, good info.  Good question too, got me thinking about it.  It's not a mental ego thing, I could train a monkey to drive a stick, I think it's a combination of many years of driving a 5-speed so it's become second nature, and my first impression of early automatic transmissions when they were inefficient, loud, slow and annoying, and failed a lot.  First impressions... time to take another look.

I drove a 2001 H4 OBW with the 4AT on city streets this week, and liked the convenience of the AT and the way it shifted.  Not like the early ATs at all.  Even with the H4 it didn't seem underpowered.  The 2007 H4 5MT OBW I drove last week was noticeably more responsive, but that's also a different engine so whatever.  I didn't like the feel of  its 5MT, it seemed notchy and hard to shift, but part of that is getting used to the feel and I think the clutch wasn't fully disengaging and needed freeplay adjustment or something.

In any case I expect the H6 with the 4AT would be a great combination, and I'm driving one (a high mileage 2001 H6-3.0 LL Bean) tomorrow so I'll find out for myself.  Gas mileage, if it really is 2-3mpg, isn't a big issue.  Cars around here don't rust at all and it's easy to spot one that has been in a rust area too long.  I'm leaning strongly toward the 2001-2004 H6 4AT based on all the helpful comments here about reliability and availability of the 4AT and 5MT, and the AT really would be so much better offroad.

[softroader]

22 hours ago, Numbchux said:

No. The extra sensors are a yaw sensor and steering angle sensor, very low failure rate. And should the system go down, it still has mechanical AWD (with an open center diff, granted) to fall back on. You'll loose ABS, VDC, and VTD functions, but it won't leave you stranded.

I'm lost here.  What does this mean?

[1 Lucky Texan]

If someone put synthetic lube in that 5spd you dove, that could explain some 'balking' when shifting. Because the trans and it's synchros share housing/fluid with the front diff, non-synth GL-5 is usually best. Full synth causes the synchros to be too fast or something...MANY people tinker around with finding their favorite 5spd lube. There's a huge thread devoted to the issue at NASIOC.

[softroader]

3 minutes ago, 1 Lucky Texan said:

If someone put synthetic lube in that 5spd you dove, that could explain some 'balking' when shifting. Because the trans and it's synchros share housing/fluid with the front diff, non-synth GL-5 is usually best. Full synth causes the synchros to be too fast or something...MANY people tinker around with finding their favorite 5spd lube. There's a huge thread devoted to the issue at NASIOC.

Interesting, hadn't though of that.  So the 5MT isn't normally notchy like I experienced?  I have only driven one so far.

Too slippery gear oil causes synchro problems because they rely on having enough friction to spin up.