The Popular BMW B58 Inline-Six Engine Has One Big Achilles Heel

Bmw M340i Achilles Heel
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The BMW B58 inline-six is a darling of the European car tuning scene. With a closed deck block, forged connecting rods, and a forged crankshaft, it seemed like BMW finally learned from its N54 direct-injected boosted-six stumbling block and created a juggernaut. However, to long-time BMW owners, one question lingered — how would BMW, um, BMW the B58 up? Well, it turns out that some of these boosted sixes are suffering from serious oiling system issues at relatively low mileage.

Make no mistake, the B58 is an absolute beast of an engine, capable of slingshotting a 3 Series from zero-to-60 mph in under four seconds, and willing to crank out more than 400 horsepower to the tires with simple bolt-ons and a tune. It’s been available under the hood of just about every BMW on a longitudinal platform in the past few years, and this single-turbo three-liter inline-six is as smooth as you could possibly want. However, earlier examples of the B58 have one achilles heel because BMW decided to make the oil pump rotor housing out of plastic.

In theory, this was a great idea. Plastic is less thermally conductive than steel or aluminum, lightweight, and could reduce parasitic losses. Unfortunately, plastic also gets brittle with age and in cold temperatures, and as oil tends to thicken in the cold, you can probably guess what happens next.

G-series B58 owners in cold climates – check your oil pumps! We’ve had two almost new cars in our shop since february with blown engines due to the oil pump failing in freezing conditions. BMW have made an updated oil pump which replaces duoplex plastic with metal. The pictures speak for themself????
byu/mariusrisan inBMW

Yeah, that’s pretty gnarly. Oil pump failure is something you never want to encounter, and to make matters stranger, symptoms for a failed oil pump on older B58 engines run the gamut. Some report excessive oil pressure, some report insufficient oil pressure, some simply report a whining sound. The common thread? If you let any of these symptoms go for too long, you could be saying goodbye to your engine.

Screenshot 2024 06 14 At 9.48.10 am

According to the forums, being unable to check oil level through iDrive when the oil is hot is a fairly solid symptom of oil pump issues, as dramatic fluctuations in pressure will lead to the test automatically being canceled due to the self-testing function requiring tight tolerances in the oil pump.

Screenshot 2024 06 14 At 10.34.27 am

As for affected models, they’re all over the map, but failures do seem to be most common on BMW’s crossovers, specifically vehicles like mid-2020 production and earlier X5s and X7s. However, early G20 M340i owners aren’t immune either. Many 2019 and 2020 examples without the high-performance cooling and tire package (option code ZTK) came with an oil pump featuring a plastic rotor housing, and owners have reported oil pump failure, sometimes with fewer than 30,000 miles on the clock. Curiously, the ZTK oil pump, part number 11419895359, has superseded the old regular oil pump, indicating that models newer than 2020 may not have this issue.

Weirdly, all this talk about oil pump failure is somewhat reminiscent of oil pump nut failure on M54 engine of the early 2000s, except a bit worse. In those engines, the nut holding the oil pump drive sprocket would back out under prolonged enthusiastic driving, with catastrophic results. On the B58, the failure mode is a little different, but the end result could be the same.

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Alright, so let’s say that you own a B58-powered BMW that’s out of warranty and want to get this issue fixed. Figure around $1,200 in parts, but as replacement requires dropping the subframe, labor won’t be cheap. One poster on Bimmerpost was quoted $6,000 for oil pump replacement in their X5, and it’s easy to see why, given how the B58 places its timing components on the back of the engine, and the oil pump is driven by the timing system. Regardless of dealer service or saving money and going to an independent specialist, this isn’t a cheap fix, being financially up into what used to be M car repair territory. Ouch.

So, if you own a 2020 or older BMW with the B58 inline-six or are looking at one as your next daily driver, you might want to keep an eye on your oil pump. Failures seem widespread enough to render this a relatively common issue, and it wouldn’t be surprising if this becomes the modern BMW equivalent of Porsche’s infamous IMS bearing.

(Photo credits: BMW, Bimmerpost)

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64 thoughts on “The Popular BMW B58 Inline-Six Engine Has One Big Achilles Heel

  1. This is why I wasn’t excited about the Ineos Grenadier, having a BMW engine seems counter to the mission of the vehicle. Like any other BMW, you have to dump it before the warranty runs out.

    1. To be fair, this is an issue with older B58 engines and there are better oil pumps on newer ones, such as the detuned B58s in Grenadiers.

      I’ve been skeptical about the BMW engines in Grenadiers as well, but so far it sounds like the B58 is an exception to the usual BMW unreliability. Supposedly Toyota had a lot of influence in its design since it was to be shared between them, so… we’ll see how they do long-term. I think they deserve a chance, and could perhaps end up being the one decent used BMW engine.

      1. have a transit with a detuned eco-boost. am a fan. funny, used to want to extract more power from everything. but today’s power levels are enough

  2. Thus following the normal life cycle of a BMW engine. Lauded for performance while under warranty. A financial train wreck for second owners.

  3. Thus following the normal life cycle of a BMW engine. Lauded for performance while under warranty. A financial train wreck for second owners.

  4. Interesting. I’ve been on an M240i forum for years now and this isn’t much of a topic of conversation. Perhaps just not something that happens as commonly on them.

    1. Same, I own a G30 and this is the first time I hear about this. I just created a topic in my usual forum showing other owners this article.

  5. Interesting. I’ve been on an M240i forum for years now and this isn’t much of a topic of conversation. Perhaps just not something that happens as commonly on them.

    1. Same, I own a G30 and this is the first time I hear about this. I just created a topic in my usual forum showing other owners this article.

  6. Seems to me that it couldn’t be a true BMW if it didn’t have at least one Achilles heel.

    BMW decided to make the oil pump rotor housing out of plastic.”

    This reinforces my view that BMW has lost its way. In the past, BMW was all about the quality under the skin and the driving experience… and not relying on superficial bells and whistles.

    These days, the company that is closest to what BMW used to be is Tesla.

    1. Actually, BMW has had significant issues in the past due to poor choices in materials. The radiatiors in the E36 cars, for instance, had a plastic neck that was guaranteed to crack after enough use. This, of course, resulted in all of the coolant blowing up and out of the system and more than a few blown head gaskets. They stubbornly stuck to those plastic radiator parts year after year and for a number of other engines and models as well. If you were on to this, you did a periodic prophylactic radiator swap.

      So you might say that they’ve kept true to their way rather than lost it (and not in a good way at all).

      1. This. I had to replace my entire cooling system on the Z4 because of shitty plastic used everywhere: expansion tank, thermostat housing and radiator.

        1. It’s not an engineering secret that plastic degrades in the presence of heat, oil, etc. And these aren’t exactly minimum price third world vehicles. Poorly done, BMW!

      2. I think the E36 is generally considered the turning point. Everything before it was pretty simple, solid, and reliable. E36 generation is when they started adding more bells and whistles and reliability started sliding.

  7. Seems to me that it couldn’t be a true BMW if it didn’t have at least one Achilles heel.

    BMW decided to make the oil pump rotor housing out of plastic.”

    This reinforces my view that BMW has lost its way. In the past, BMW was all about the quality under the skin and the driving experience… and not relying on superficial bells and whistles.

    These days, the company that is closest to what BMW used to be is Tesla.

    1. Actually, BMW has had significant issues in the past due to poor choices in materials. The radiatiors in the E36 cars, for instance, had a plastic neck that was guaranteed to crack after enough use. This, of course, resulted in all of the coolant blowing up and out of the system and more than a few blown head gaskets. They stubbornly stuck to those plastic radiator parts year after year and for a number of other engines and models as well. If you were on to this, you did a periodic prophylactic radiator swap.

      So you might say that they’ve kept true to their way rather than lost it (and not in a good way at all).

      1. This. I had to replace my entire cooling system on the Z4 because of shitty plastic used everywhere: expansion tank, thermostat housing and radiator.

        1. It’s not an engineering secret that plastic degrades in the presence of heat, oil, etc. And these aren’t exactly minimum price third world vehicles. Poorly done, BMW!

  8. Hi Thomas,

    It would be great to post part numbers for the problematic pumps to avoid general panic. As the owner of a B58 powered G30 5 Series, this is concerning but at the same time I have never seen this been an issue in any forum. Perhaps the issue is overblown or isolated to very specific pumps not used in all B58 engines?

    My car has a Mahle pump, part 11417643046 and it has no relationship with the 11419895359 pump you referenced.

    The Reddit post is also 3 years old and hasn’t seen more posts since it was created.

    1. So, after some quick digging, this is the allegedly problematic pump and here is the list of BMW models and production dates that use it. It was used only for a bit more than 1 year between 2018 and 2019 and only for certain B58C and B58D engine revisions. Not to say other pumps didn’t have plastic housings, but again, I think this is a bit overblown, especially considering the myriad B58s that are tuned to hell and using their stock pumps.

  9. Hi Thomas,

    It would be great to post part numbers for the problematic pumps to avoid general panic. As the owner of a B58 powered G30 5 Series, this is concerning but at the same time I have never seen this been an issue in any forum. Perhaps the issue is overblown or isolated to very specific pumps not used in all B58 engines?

    My car has a Mahle pump, part 11417643046 and it has no relationship with the 11419895359 pump you referenced.

    The Reddit post is also 3 years old and hasn’t seen more posts since it was created.

    1. So, after some quick digging, this is the allegedly problematic pump and here is the list of BMW models and production dates that use it. It was used only for a bit more than 1 year between 2018 and 2019 and only for certain B58C and B58D engine revisions. Not to say other pumps didn’t have plastic housings, but again, I think this is a bit overblown, especially considering the myriad B58s that are tuned to hell and using their stock pumps.

  10. Ahh, the universe as it should be. It is comforting that any BMW owner knows exactly what to expect and gets it 100% of the time. This is priceless brand consistency, and Mercedes and Audi are learning too.

  11. Ahh, the universe as it should be. It is comforting that any BMW owner knows exactly what to expect and gets it 100% of the time. This is priceless brand consistency, and Mercedes and Audi are learning too.

  12. So on top of a plastic oil pump on a “more performance focused engine” that also has no dip stick, meaning you have to check within the screen, it also runs its oil pump off the timing system which is at the back of engine… I swear BMW makes the most confounding decisions. I don’t even want to know the quote to do timing chain guides on a B58, given that’s almost guaranteed to be an engine out job.

  13. So on top of a plastic oil pump on a “more performance focused engine” that also has no dip stick, meaning you have to check within the screen, it also runs its oil pump off the timing system which is at the back of engine… I swear BMW makes the most confounding decisions. I don’t even want to know the quote to do timing chain guides on a B58, given that’s almost guaranteed to be an engine out job.

    1. Had the 135i been in production when I retired, I would have bought one. But I wanted a new car as a retirement gift, and I thank my lucky stars regularly.

    1. Had the 135i been in production when I retired, I would have bought one. But I wanted a new car as a retirement gift, and I thank my lucky stars regularly.

    1. From the same country that brought us some of the greatest hits of automotive plastic such as the Boxster coolant tank and the VW EA888 water pump/thermostat housing!

      1. My mom’s A4 Allroad with the EA888 mechanically totaled itself at 60,000 miles. When I had one in a GTI I bought new the thing misfired for the first year of its existence and VW techs gave me a range of responses from “yeah, this motor just does that” to “have you been using VW approved gasoline?”

        …seriously. He then handed me a list of VW’s preferred gas stations. On top of that it was having issues starting when I eventually got out of it…with 14,000 miles on the clock lol. It was probably the spark plugs but I didn’t wait around to find out.

        Fuck that godforsaken engine. What do we say to plastic engine components?

        NEIN!!!!

    1. From the same country that brought us some of the greatest hits of automotive plastic such as the Boxster coolant tank and the VW EA888 water pump/thermostat housing!

      1. My mom’s A4 Allroad with the EA888 mechanically totaled itself at 60,000 miles. When I had one in a GTI I bought new the thing misfired for the first year of its existence and VW techs gave me a range of responses from “yeah, this motor just does that” to “have you been using VW approved gasoline?”

        …seriously. He then handed me a list of VW’s preferred gas stations. On top of that it was having issues starting when I eventually got out of it…with 14,000 miles on the clock lol. It was probably the spark plugs but I didn’t wait around to find out.

        Fuck that godforsaken engine. What do we say to plastic engine components?

        NEIN!!!!

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