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Should Subaru Develop a Diesel Vehicle for the US?


Should Subaru Develop a Diesel Vehicle for the US?

I seem to get a quite a few questions about whether or not there will ever be a Boxer diesel imported into the U.S. by Subaru?  The answer is no one really knows for sure and that includes Subaru, they did initially plan on doing so but the market place changed in a few different ways in 2011 with those changes known about for a few years prior.   I will take a few minutes to explain some of the headwinds preventing the Subaru diesel from potentially ever coming to the U.S.

Other parts of the world seem to get all of the cool stuff if you are an enthusiast; this has been true for years and has always been about government regulation here in the U.S. VS the rest of the world.  Many twin turbo model legacy vehicles from the mid 90’s would never run properly on the fuel we serve at the pump in the states.  The same issues are present for Subaru to import in the Diesel Boxer engine.

In the US we regulate the emissions produced by Diesel vehicles in a different way than in Europe caring more about the content out of the tailpipe rather than the Volume.  This creates a situation where the fuel economy of many diesels right now are not as good as they were just ten years ago, yes we have seen a fuel economy decrease across the board starting in 2004 with a few exceptions.  There are many factors for this but the primary reason is that diesel fuel is used to cool the exhaust to help reduce NOX emissions (see here for explanation)

A portion of the diesel fuel used in a combustion cycle doesn’t actually go towards powering the vehicle but instead is used to lower the content of the tailpipe which creates a very inefficient situation.  This is also known as the third injection event.  Light diesel trucks were averaging up to the mid 20’s for fuel economy prior to 2004 ½ when the first of many regulations took effect, then again in 2007 and finally in 2011 the new clean diesel rules are in full effect resulting in fuel economy well under 20 mpg and actually closer to the tens and low teens!

While it’s true that Volkswagen, Audi and Mercedes all have a clean diesel in the US, it’s also prudent to point out that they command a price premium that the drivers are willing to pay, and are not as efficient as they once were.  Subaru fits into a different space than the German Vehicles and may have a tough time selling a Diesel vehicle that commands a higher price with a very long term of payback VS a gas engine.  Instead Subaru Has focused on the CVT transmission as a way of improving fuel economy in an AWD vehicle.

Where we are at right now is that the Automakers must spend money into development of better ways of reducing the content of the tail pipe emissions to satisfy the U.S. regulations while at the same time improving fuel economy to the point where it makes sense to pay more for a Subaru vehicle equipped with a Diesel engine and also pay more at the pump as Diesel is more expensive than gasoline due to the high refinement costs also associated with regulation of the content of the tailpipe in the way of ultra low sulfur diesel fuel which costs more to produce than diesel did 5 years ago.

Fuel economy has been on the rise for the diesel platform in the light duty domestic truck from the big three,  but they are also commanding an extremely high price. Adjusted for inflation a diesel truck just does not make economical sense for anyone right now, its only about the want factor.  Translate that into the want factor for a Diesel Subaru and they would sell a few but it would be a very low volume vehicle, as the sticker price would discourage many people.  Subaru has shown as of late that they want to continue to increase US sales volumes which means they have to keep the focus on what the majority of drivers want and can’t afford to dabble in the lower volume vehicles that they have tried in the past.  Part of this comes from the heavy influence from Toyota who owns a rather large chunk of Subaru having purchased General Motors 16% stake years back.

As an enthusiast I had hoped we would have a diesel Subaru in the US by now.  As someone who follows the auto industry in whole I understand why it may be very difficult to make it happen.

I will add that with the extreme disparity of Natural gas price VS Gasoline and Diesel we may actually see a CNG vehicle from Subaru before a diesel as the payback would be much quicker with  the  2 dollar a gallon savings.  The current obstacles to CNG is the range and lack of fueling stations or investructure.  If Automakers started to actually build vehicles designed to run on CNG they could incorporate larger storage systems into the vehicle whereas now most are conversions with a tank added to the trunk cutting down the cargo capacity of the vehicle and still only having a range of  around 200 miles.  If sales start to stall out for what’s available right now we could finally see a shift to a fuel that would slash our dependence on foreign oil plus a thousand other benefits.

That is until the EPA and Department of Ecology found something they needed to regulate, raising the price of the fuel and the vehicle.

Thanks for reading and please share your opinion about the Subaru Diesel!



38 Responses

  1. I have been driving a 2004 golf tdi since being converted to diesel with an old mercedes. i consistently killed the engines in 5 gas powered cars driving the hills here in california. the tdi just takes all road conditions except water in stride.
    I had the 1999 subaru with automatic and loved the handling but hated the transmission, then killed it.
    I am one of 10 here in northern california that would instantly buy a manual transmission diesel forester.
    One keeps hoping.

  2. A Boxer Diesel in a Baja, now there would be a vehicle to launch in the US.
    Forget emissions, time to change the laws for logic and reason, not at the whims of some environmental groups.

  3. It seems unforgivable that the Boxer Diesel has not been allowed entry into North America. Is diesel for everyone? No, not really. Some people may be put off by the clattering noise that’s characteristic of the diesel engine. Some might not like the smell of what comes out of the tail pipe. Some might not like not having an automatic transmission as an option. But so what? If you know how to drive a manual shifting transmission and you want a diesel engine, and you can afford the extra cost of filling up on diesel, one should be allowed the option.

  4. thank you for your informative article. I would buy a diesel cross trek or legacy in a heartbeat if priced between $22 and $28k.

  5. I’m driving a 2010 2.0 diesel legacy in Europe, and I drive now diesel for nearly 15 years. My experience with the legacy is pretty good. The only issue that you have to drive it like a diesel, and you can not tune the engine like the petrol. This is a Euro 5 engine, and if you check every diesel In the US fulfill Euro6 norm. So I think in a short time when Subaru release his Euro6 engine, should be no problem to get it in US. Only Subaru has to decide to sell it.

  6. With the number of CNG fueling stations now available, and new ones now being planned and built, the CNG Outback model which is available elsewhere should be sold in the US also. Otherwise, unfortunately, I may have to leave Subaru and buy a Honda Civic CNG. Compressed Natural Gas is lower cost, has improved emissions, and is American-produced.

    1. With Fords announcement That they will offer a CNG version of the F150, that should pave they way for more CNG vehicles, but at this time I am not aware of any Subaru Vehicle running on CNG, I know Sweden intended to do some factory conversions, but I have never read any follow up to the 2011 press release.

      CNG in a truck makes sense because of the storage, it could be hard to do on a car due to storage constraints.


  7. I drive a gasoline Outback now and in a few months I’m buying a new car. I want the Subaru Turbo Diesel Outback but Subaru won’t bring it here so I’m buying the VW Passat Turbo Diesel. 18.5 gallon fuel tank. 30 city. 43 on the road. Subaru lost this sale. Too bad.

  8. Could the cooling of emissions to lower NOx be achieved by adding an extra intercooler? I’ve seen SH Forester N/A to turbo conversions that use the N/A hood (no scoolp) and locate an intercooler under and in front of the radiator. If you had a similar cooler located in the front end and run cooling lines by the exhaust manifold, would that create enough cooling to lower NOx?

  9. The question in my mind is whether the US emissions regulations do result in better air quality.

    As regards many motor vehicle standards/regulations, the US usually seemed so far behind European standards, stifling innovations and creative solutions such as Citroen’s steerable headlamps. And cars with side-mounted winkers are just starting to show up in the US. That’s a great safety feature—assuming drivers actually USE signals (!).

    There are many extremely efficient cars available in Europe, cars without the complexity of the hybrid design.

    If the US were serious about fuel economy, the rules, I think, would change. But the price of fuel isn’t yet high enough to warrant such changes, and US citizens are hooked on large luxurious cars. Fuel economy is not as high a priority as bling. Too bad. Fashion statements are all right but better to wear them on your person.

  10. I bought an ’09 Legacy because I need an AWD vehicle…it was my first Subaru…I’m impressed with the overall quality and warranty service I have received. But, the diesel AWD would be an awesome vehicle as a Legacy…I would have bought the VW Jetta TDI, but no AWD…and the price of the VW was competitive…so I’m sure they could do the diesel and keep it relatively affordable….

  11. Pitrack is right – the DPF problems with Subaru diesels will come out and bite you sooner or later.

    Sadly it`s worse than that – however.

    ALL European diesels suffer from the same problems – blocked DPF`s, failures of DMF (dual-mass flywheels) – turbo failures due to lubrication problems – high pressure injection systems (Piezo-Electronic) with dodgy and VERY expensive injectors – an almost complete intolerance of anything but the best quality diesel fuel.

    I was seduced by a 1.6litre Ford Focus turbo-diesel with a fantastic specification- 236lb/ft of torque @2500rpm on “over-boost” and amazing passing ability – matched my V8!

    Bad news – by 60,000 miles, turbo failure, DMF rattling a bit (Help!), DPF OK but I don`t do urban traffic; 2nd turbo on the way put after 2000 miles – another $1500? Previous failures (non-diesel) have cost $2000 or so.

    On a car at this mileage? My last Euro Ford did 250,000 miles – and that had a good AWD system very like Subaru.

    DON!T go for a Subaru diesel! Fuji Heavy Industries has neither the resources nor the experience to get this right.

    The first batch of Legacy Diesels arrived in the UK in 2008. Since then there have been a wave of failures- particularly of the flywheel and clutch. It would seem these components were borrowed from high-performance turbo petrol Subarus. But, the chacteristics of a turbo diesel are quite different – basically chucking huge wallops of torque at the transmission at very low rpm. (Check the Ford Focus above! But that has a gearbox designed also for diesels in light trucks with massive torque. Ford are good at gearboxes).

    Subaru are NOT good at gearboxes – the price of sticking all that AWD stuff into one casing is a very long main-shaft in the gearbox; plus, the input gears have to lie above the centre of the final drive (which means so does the engine – “sucks” to “low centre of gravity with boxer engine” – this is a myth.

    So you are anyway at risk of destructive tortional vibrations in the drive line. An auto Subaru diesel might be quite another matter. But, like I said, Fuji HI are not big enough to do their own thing here – anyway they buy in their auto-boxes from ?Aisan? (Justin – please clarify!)

    I tried the Subaru Outback diesel here in the UK – not a new demonstrator – but a 4 year old with 80,000 miles up.

    Answer? I thought it quite a nice car. My 1.6 Ford Focus TDCI wagon would eat it on acceleration (about the same weights). The power came in late – around 1700 rpm. Before that it was “gutless” – you had to rev it to get the turbo working. I concluded it would be useless as a towing vehicle – you`d have to risk burning the clutch to get it going on a hill start. There is evidence here in the UK of serious transmisssion failures as a result of this characteristic. (Look for “Honest John” on Wikipedia UK – he`s a good witness)

    There is no low-range on the diesel gearbox – that gearbox simply cannot handle the torque.

    Subaru for the 2009+ model have fitted a 6 speed gearbox – presumably because (being used in the turbo Spec B) they think it will handle the diesel`s torquw better. Live in hope! At the same time, I read (see HJ above) that the 2009+ diesel has a modified ECU to reduce the torque of the engine, in order to protect the transmission.

    I hope this helps A final word – if you think European diesels really ARE motoring Valhalla, ask yourself whether the USA is likely to distribute the kind of high quality diesel the Europeans get?

    In my view, that`s the main reason why the USA is not getting the Subaru diesel.

    Me? I decided to stick with the basic Subaru wagon with a 2.0 litre petrol; these are not sold in the USA but I have two – the old one WAS built in the US in 1998 before the model change. 14 years and still good. The later one is a 2003 (2005 to you!)which is a very sweet (EJ202) engine.

    2.0 litre Subarus do not eat their headgaskets! I`d love an Outback, but that comes with the troublesome 2.5 litre engine all you US owners have grown to know and love.

    Hope this helps.

    Bottom line: FORGET Subaru diesels.

    They will be nothing but trouble.

    Andrew Sanders

    1. It seems crankshafts are breaking as well- people have posted pics. Quite a few unhappy Europeans out there. I don’t know if this could perhaps be related to performance modifications.

      Having said that, it’s been a lot quieter in the past year regarding driveability (shudder) on the chat groups…Subaru may have sorted several issues.

      Andrew, re: Focus@60k… almost sounds like the 70’s and you’d bought a Leyland, except it’d be @6k miles 🙂

  12. Everyone please call 1-800-Subaru3 and voice your opinion. They will listen to us if we all call. They are missing out on a huge financial opportunity by not bringing the diesel line to the U.S.. As others have said, “it’s a no brainier”, but that’s the problem with marketing teams. They having little to no brains. lol. Sometime in life we must take chances if we seek big rewards. Take a chance with us Subaru. Give us a chance to own a Subaru Diesel. I’ll be waiting.

  13. I’ve been working in Italy since the start of 2012, and have driven 8 or more different brands of cars here – all diesels. Back in the US I have a VW Passat tdi, jetta tdi, and a GMC Suburban diesel in my family. I can say for certain that the cars I’ve driven here all get much better fuel economy than the diesels sold in the USA.

    All of them (2012 models: VW Golf & Touran, Fiat Punto & polo, Lancia Delta, Audi A3, Ford Cmax, Nissan Qashqai, and maybe one or two others) have manual 5- or 6-speeds. While low-end power is variable on them, it’s generally low below 1500-1700 rpm. Above that, the power is usually great for small 4-cylinders. And the tall top gear means that cruising on L’Autostrada at 80 to 100 mph is fine, while the great fuel economy is maintained. I didn’t measure fuel economy consistently on all the cars, but the best was probably the jetta – I would get close to 60 MPG when most of my driving was a 15 mile commute (50mph speed limit or thereabouts) on primary roads and a few trips on the Highway mixed in. The worst was probably the Nissan or Ford. I had too much fun driving the Audi to worry as much about economy.

    I found this page, because I think the best package I could imagine is a Subaru AWD with a diesel. It’s a shame that the focus in the US is on tailpipe emissions rather than low consumption. We lose probably 25% or more on economy, and I can’t imagine that the US system lowers emissions more than that.


  14. Justin,

    firstly thank-you for all the considered, factual and logically laid out information regarding head gaskets. Now if only you’d establish a branch down here in Canberra Australia I could get some decent and independent service 🙂

    I was wondering your opinion on what the diesel engine one is likely to be like compared to the petrol versions?

    As for those wishing for the Subie diesel, be careful what you wish for, you just might get it: Diesel Particulate Filter (DPF) regenerations, shuddering, forced regens, drivability issues, restricted operation envelope and compromised performance all can raise their ugly head, along with other issues. It may be the Euro 5 closed-circuit DPF is the ‘bridge too far’ / straw that broke the camel’s back, given this is the first consumer passenger vehicle diesel boxer engine developed by Subaru.

    During a DPF regen, which occurs without warning, the performance (and economy) drop off dramatically. Sharp persons can pick an idle sound change (I can’t hear it at speed) and will see the instantaneous fuel economy under throttle worsen by approx 2l/100km or more (should be watching the road).

    All will feel the performance degradation under acceleration, which is akin to turning the turbo off and/or dropping 2 cylinders. This persists for 4 seconds before the Exhaust Gas recirculation (EGR) valve closes (often can be heard) and the turbo spools up again- all within the supposed and recommended 1800-2400rpm max torque range.

    In Australia, there is a lot of single lane, 100km/h road. There is also an expression, “hung out to dry”, meaning someone in need who’s been abandoned. So whilst trying to overtake at 100km/h, your engine, without warning, cuts your performance for at least 4 seconds. 100km/h = 27.78m/s x 4secs = 111 metres before you get performance back. But the oncoming vehicle is doing the same speed, so you’ve lost 111 x 2 =222 metres before your vehicle stars to accelerate. You’ve been “hung out to dry”- “hung out to die” may be more appropriate! It happens. To me. With a wife and infant on board. The Subaru euphemism in the handbook is: “When soot is being burned in the diesel particulate filter, the driveability, engine revolutions, engine sound and smell of emission gas may change.” That’s all they give you.

    When it’s functioning normally, it’s a sharp, snappy performer especially at speed. But as I said, DPF regen occurs without any warning. On hills it leaves the vehicle sagging on revs below the turbo’s effective point (~1600rpm) causing downchanges which, on steeper grades, start also sagging (EGR reopens as you change gear, resetting the 4 second delay). And try running up a twisty mountain pass with a 4 second lag for powering out of the apex… tried a 4 second preempt on the accelerator leading into a corner which means accelerating somewhat into it or accel+braking simultaneously? It destroys the fun. And the 2litre 4-cylinder behind you (let alone a V8) isn’t too happy either. So like a recidivist criminal offender, you learn to never trust the vehicle to perform when you need/like/want it to.

    The vehicle won’t tolerate stop/start conditions for extended driving either, or the DPF will require a forced regeneration by the dealer.

    Top that off with driving characteristics unfamiliar to most diesel drivers (no low torque, stalls easily at idle, requires revs but is rev limited to 4750rpm), a strangely geared manual with no auto box option and it’s not the sort of thing I would expect U.S. citizens would put up with. I would suggest the chance of brand damage, as well as irate customers (or relatives) launching some sort of legal action would be in Subaru’s mind.

    Several engineering changes have been made to newer MYs (in spite of no nominal power/torque differences) which may have addressed some or all of these issues.

    Pitrack_1 (2010 Forester Diesel 56000km)

    1. It’s a shame the performance dropoff is so abrupt and profound. You would think it would be an easy SW fix in the ECU to either A) allow the driver to initiate a manual regen cycle by pushbutton before a need like overtaking, or B) provide a 30 or 60 delay in the regen cycle when the power output is over some threshold – 75% maybe. Or maybe C) add some indicator that a regen is about to occur. But what do I know. Maybe if consumers provide enough feedback – along with helpful suggestions, the Subaru engineers can introduce some tweeks to the way the regen cycle is implemented.

      1. The 2.0l is to small to overcome the power robbing act of the Regen cycle, they will have to figure out another way to make give Diesel a broader based appeal.


  15. I have heard that in 2014 the Europe diesel emissions standards are almost identical to the US. Couldn’t the diesel be introduced to the US at that time. VW is increasing production for their diesel vehicles because of the strong demand so it would make sense to me.

  16. It seems unfair that other countries get to benefit from Subaru’s Boxer diesel engine, but we Americans don’t. When you consider the benefits of Subaru’s Boxer engine, and then add a Boxer Diesel to the choice of engines, there seems to be no reason such an engine shouldn’t make it to this country. Forget what the marketing people say. We, the Subaru drivers and owners should be the ones who make the decision. Have a nice day.

  17. Justin… great article, thanks!
    I just wish I could buy a vehicle that gets 45- 55 MPG and has the pep and steam that the VW diesel has in the JETTA… I drove one and it is amazing.. Only problem is that I live in the mountains and couldn’t get up the road because the JETTA is only front wheel drive.. DANG, can’t somebody just do BOTH THINGS RIGHT?? Give me the VW DIESEL and the SUBARU AWD.. and I’ll be in Heaven!!

    Bald Head

  18. Hi Justin,
    I believe that subaru should bring the diesel to the U.S. and a great “experiment” vehicle would be the XV Crosstrek, maybe in a year or two. If equipped with a heavier duty CVT, (unfortunate as it is that America is so dependent on the automatic) it would be appealing for many subaru owners that actually own their vehicles longer than 38 months (or whatever the average is for the typical american car owner)Despite my bias of being a huge subaru fan and wanting a boxer diesel personally, i believe subaru should give this engine a chance in the U.S, the demand is there, especially with the market niche they already have!

    This website is excellent! I’m 18 years old and your attention to detail and insight has inspired me to pursue my passion for cars, and subaru’s in particular.

    Fingers Crossed,

  19. Subaru has cng and diesel powered boxers in the rest of the world, and these systems seem to work fine and are efficient.
    so whether we get one of thee or not is a marketing decision on subaru’s part.

    btw thank you Justin for your blog insights and excellent videos.

    1. Thanks for the Reply Nat!

      I agree its a marketing decision, I am just not sure you can effectively market a more expensive vehicle obtaining only fractionally better fuel economy than what you currently offer. If we regulated Diesel engines like they do in the UK I believe we would have one here already. The 40 to 50 mpg that the Diesel Forester is obtaining in Europe would most likely be in the 30’s here and have a higher production cost due to the emission control devices that would need to be in place.

    2. Just a reality check on Compressed Natural Gas – it will never be viable as a fuel for cars driven other than local commutes as it takes overnight to compress the fuel to the 3000PSI compression required, so in other words you can’t just fuel up along the way on a long trip. Currently regulations require tanks to be annually inspected and any failure requires expensive tank replacement and you can’t just swap tanks either if you are on a long distance trip. Oh and that is ignoring the part that CNG is the least efficient of all current fuels. Fuels rank Diesel@110%, gasoline@100, LPG@74, Ethanol@66, LNG@66, Methanol@49 and Compressed natural gas at the bottom of the heap @25. That’s why it’s so cheap, you’re not getting the same bank of power for the buck. Now you can see why the US consumer needs to wake up on the merits of diesel as a power source and that’s not even addressing the superior longevity of the engines inherent in the fact the fuel is a lubricant which greatly reduces internal wear.

      1. HI Eric,

        I agree with the need for more Diesels, but some of the information on CNG (Compressed Natural Gas) is not all factual I am afraid. Also LNG (Liquid Natural Gas) is another solution. CNG does not pollute as profoundly as diesel, even without a array of add on devices to help clean up the vehicle. A Truly built to run on CNG vehicle VS a conversion does not have all of the challenges you have laid out. Most vehicles have a yearly smog type test, so a yearly tank test should not be a big deal.

        I am a big proponent of Diesel, but given the abundance of NG, its not hard to see a change coming that way.

        The instant Government subsidence big oil for NG, there will be a huge market place.


    3. I hope soon they will bring them into the country. I would like to get a Forester with the diesel in it. Why is it taking so long?

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