My BMW Just Found A Hilarious New Way To Fail Me

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My BMW 320D was an impulse purchase. It’s quickly becoming a lesson on why those are often a bad idea in the car world. Thus far, I’ve contended with fueling issues, a recalcitrant transmission, and an interior door handle so sticky it threatens the very fabric of my relationship. But this latest failure, oh. It knew I had big, important plans, and it struck me right where it hurts—my incredibly tender hip pocket.

When last we spoke, I thought I had it licked. Replacing the fuel quantity control valve had sorted the car’s hesitation issues. The transmission stopped shifting poorly soon after, likely because it wasn’t getting surprise torque spikes from the inconsistent fuel delivery. I was ready to enjoy the car; heck, I was ready to sell it. I took it out for a couple of spirited drives, enjoyed the E90’s wonderfully balanced handling, and figured the best time to sell a BMW is when it has the minimum number of warning lights on the dash.

I got cocky. Speaking to the gang in Slack, I outlined my grand plan to sell the BMW to fund a future convertible purchase. I’d rely on my iffy-but-trusty Mercedes E240 in the meantime. Literally, I was just waiting for the weekend, all set to list the 320D this coming Sunday night. And then I did the stupidest thing possible—I drove it to McDonald’s.

I was working my way down the highway at a handsome 50 mph, admiring my good hair day … when I heard a clunk. Or, indeed, a pair of clunks. “That sounded like me,” I mused. And yet, the car seemed unbothered, so I elected to drive on. Denial, the first stage of grief.

Thirty seconds later, though, truth rang home when the “Charging Fault!” warning flashed up on the dash. Okay, so it threw a belt. I figured I had a good ten to twenty minutes before the battery ran out, but I didn’t want to push things. I decided to pull off the highway, only to get stuck at a light for TWO WHOLE CYCLES. Anger.

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Nonetheless, I got the car parked up five minutes later and went under the hood to inspect the carnage. I was honestly a little surprised. Expecting a shredded mayhem of rubber, instead I found a seemingly-intact serpentine belt merely sitting off the pulleys. I soon realized that this was probably not the ideal result. A snapped or destroyed belt would suggest a belt replacement might fix the problem. An intact belt suggested issues with pulley alignment, tensioners, or other fiddly things. The presumed bill in my head had started at around $50; now I was adding a 1 or a 2 in front of it.

I elected to leave the car, not wanting to fiddle with it on an empty stomach, nor limp it in heavy traffic. I returned post-nightfall, fresh for more investigation. Maybe it wouldn’t be so bad! Maybe I could lever the belt back on and see how it goes for a few days? Bargaining. 

I popped the hood, propping it up with a large stick from a gum tree because the gas struts are shot. The belt came out freely, and I peered into the engine bay to figure out my next move. I figured I’d start by trying to get the V-belt on to the crank pulley first, before winding it around the accessories. Something was strange, though. The crank pulley, boy, it sure was awfully smooth. I thought about messaging Thomas to get the benefit of his experience with the E90 range. “Hey, the crank pulley… no grooves on these?” No, that sounded stupid even in the dark.

I didn’t have to hunt long for an answer. Shifting the flashlight around revealed the source of the ka-clunk I’d heard earlier. It was the crank pulley, or, more accurately, half of it. See, the crank pulley on the N47 diesel engine is a two-piece affair. It’s a common design, where there’s a part rigidly mounted to the crankshaft, which is then joined via a rubber damper to the part that actually mates with the accessory belt. It damps vibrations and it’s all very nice. That is, until the rubber perishes and the front half of the pulley tumbles off into the bottom of the engine bay. Big ups to the splash guard which stopped it bouncing out into the road and ruining somebody else’s day, too. Depression.

The chunky half of the crank pulley was quite something; it appears this pulley has been on its way out for some time. The rubber has separated all around and the front half has simply torn itself free from the part that’s still bolted to the engine.

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It’s kind of an interesting shape, no?

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It was now obvious to me that I wouldn’t be fixing this on the side of the road. I decided to limp the car home. I figured I’d have enough battery to keep the engine on and headlights lit for the short journey back, and threw the half-a-pulley and still-intact belt in the back.

Without the accessory drive belt, I’d be down air conditioning, charging, and power steering. The latter was the most hilarious. Now, I’m no stranger to cars without power steering.  My own Miata had a depowered rack for its quick ratio and excellent feel. A depowered E90 is something else entirely. Turning the wheel was like trying to run almost-set cement through a 19th-century butter churn. Hilariously, though, the car otherwise drove great. Perhaps even quieter than usual, given all the accessories that were no longer spinning around. I took the slow lanes and a safe route home, and made it back without too much drama. I was glad, at least, for having saved myself the additional hassle of a tow truck. Acceptance.

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I’m no rubber expert, but it looks like this has been in the process of failing for quite some time. Today, it must have been dangling by a thread, until it wasn’t.

So, what now? Well, for one thing, I’m kind of glad I didn’t sell the car last week when I first had the idea. It would have been an unwelcome surprise for the new owner to have bits falling off the engine so soon after purchase. Do I wish I’d sold it months ago? Well, that’s another question entirely.

I’m going to have to fix it, and annoyingly, it won’t come cheap. It’s going to cost me a few hundred bucks for the crankshaft pulley alone, and potentially another $50 or so for a set of sockets to deal with the hardware. Beyond that, there’s the question of whether I leave the belt and idlers alone, or change them as well. Swapping them out would be the best thing for longevity, but I’m also totally done with this car and want it out of my life. Spending more money on things that aren’t broken is not my bag of hammers.

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“IT WAS SUPPOSED TO BE OVER BY NOW!” *screams*

It’s not a hugely difficult fix, but it’s going to take a few hours that I simply don’t have right now. It looks like I’ll be piloting the Mercedes until time clears.

Really, though, I’m just annoyed at this whole debacle. The car’s got just over 100,000 miles on it. It’s not unheard of for an N47 to throw a crankshaft pulley at that age, but come on—really? I’m a lover of engines that don’t quit. My Ford Falcon hit almost 300,000 miles on its original crank pulley, and still had its original head gasket. The B6 engine in my Miata achieved much the same. Meanwhile, I’m supposed to accept that BMW can’t make a crank pulley last much more than 100,000 miles?

Okay, I’m getting back to anger now. Fundamentally, some of the fault is mine. I’m supposed to know better. I bought a cheap used BMW, even after hearing all the horror stories. I wanted to believe it wouldn’t happen to me, but it did.

That gorgeous steering feel, the supple handling that BMW was known for? Just ask a friend to give you a drive. Don’t invite this storm into your own home. Learn from me, and be stronger for it.

[Editor’s Note: Used BMWs can be great fun, but they aren’t great impulse buys. There’s a joke that every modern BMW comes with one engine that will last forever and three that will spawn class-action suits, and the N47 falls into the latter category. If you’re enticed by an E90 3 Series, either go for the N52B30 naturally-aspirated gasoline-powered inline-six like I did, or the M57D30 turbodiesel inline-six. Everything else has real problems. -TH]

Image credits: Lewin Day

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103 thoughts on “My BMW Just Found A Hilarious New Way To Fail Me”

  1. That reminds me of our 1995 Ford Escort that reminded us to change the timing belt by ejecting the rubber damper from the crank pulley every 56,000 miles or so. Since replacing the pulley got you most of the way to the timing belt that got replaced every 60,000 miles it became a “while you are there” job. Fortunately in the early oughts the whole job ran about $300

  2. Had the balancer fail on that pinnacle of reliability, the 300-6 in my 92 F-250. It took over a year to diagnose. It would occasionally move inward and rub against the timing gear cover making scary noises I though were coming from the clutch. Or randomly shred a belt. It never slipped to where it wouldn’t spin the accessories, though.

    It finally carved a hole in the timing cover so it was flinging oil everywhere and I thought my main seal went bad. It wasn’t until I took the whole mess apart that I realized what was going on. Fixed the cover with JB Weld and considered welding the old balancer together but wisely bought a new one.

  6. Had the exact same failure in a 3 series in a Lemons race once, when that one went though it even managed to warp the crankshaft by about 3mm so even after we replaced the pulley, the crank position sensor isn’t able to read the crank. Ended up only salvaging the heads in the end from that engine.

  7. I have a 2001 Z3 with the M54B25. It has almost 300k miles on it and other than some areas that need to be refreshed and possibly a new torque converter, it runs like a dream. I think I got lucky with it because it was an impulse buy but I knew it would need work.

    1. That sounds good! But also “new torque converter” does sound a bit of a hassle. Hope it keeps treating you well! 300K miles is a great achievement for a BMW.

      1. Not totally sold on the torque converter being the issue, but has I fix more things it is looking more and more like the culprit. I bought it knowing it would be a project though so it will survive to 300K+ on my watch.

    1. It’d be a hell of a find – most would likely be in similar condition to the one he has. Rubber has a shelf life, and crank pulleys aren’t usually considered consumable maintenance items.

      1. Unless that failure is what put that car into the junkyard I think it will be a *bit* better than the one he has 😉

        A junkyard part might also be newer or from a lower mileage engine. If its intact, not showing any sign of imminent failure and if its cheap enough I think it’s worth a shot.

    2. That would be a fun and cheap way to fix it but 320Ds don’t show up in junkyards out here. BMWs barely do at that.

      In any case I do want to get back to do more junkyard history lessons

  9. I swore off anything German a couple of decades ago, VW, BMW, Mercedes, Mercur, unreliable, overpriced, vindictive, spiteful spawn of hell, drainer of bank accounts begone!

      1. Someday I need to drive a properly-sorted XR4Ti. I had a SHO at the time, and felt too competitive with them to give them proper consideration. (Maybe I was suffering from wing envy.)

      2. Of the four they were the least troublesome. The xr4 started harving issues with the engine 6 months from new. The problems moved seemingly randomly through electrical, fuel, ignition, drivetrain, suspention at which point I gave up and traded it for a BMW. The Scorpio was a lightly used tradein. It was great until it wasn’t due to an engine valvetrain failure. Dealer fixed under warranty, but it never ran properly after. I suspect the dealer was the issue on both cars. They were less that enthusiastic about supporting the cars and we’re always trying to sell me a mustang.

        1. Yeah, I actually agree…when I was a teenager I wanted a Bummer but not anymore…I used to have an 84 Jetta which was fun to drive and still like old VW’s like that (Bug, Bus,etc) but no new ones…I’m sticking w/ Honda for now

          1. All except the my 58 Bus and Scorpio were new. The cars were all great, but fragile and expensive to fix. My BMW 325is had a boatload of issues from new. My. Mercedes 190e was better, but suffered from random electrical issues and ate brakes. The Merkur’s also had mechanical and electrical problems. My Bus was old and tired and a first car.Kept it for years but seldom drove it. The last was a 98 new bug. Actually a pretty good car suffering from a million niggling little problems the indifferent dealer couldn’t or wouldn’t fix. All of the dealers were craptastic and hell to deal with.

              1. Ok well I was just being a smartass because I thought it was odd to include Mercur along with those brands. That’s pretty cool that you had one of each, bet there’s not more than 10 others who could say that.
                I wrenched on an parked cars back then, the Scorpio’s interior was awesome. As good as the Acura “Sterling”.

                1. I was a fool for cars back then. A friends sisters husband was a Ford area rep and let me drive an xr. Got hooked on it. Got a great deal through him. The Scorpio just called out to me after being mauled by the BMW and Mercedes. The Scorpio did have a sweet interior. I figured what the hey, it’s a Ford so it should be better than the others. Another assumption shot to heck. I’ve only seen pics of a Sterling. I don’t recall them ever coming to Canada.

                  1. I don’t think the Sterlings made it up there. But take a “Honda” Legend, iron some stiff creases into the bodywork, and give it a full-on English drawing room interior. Oh, and those lovely Lucas electrics.

                    1. I’ve got direct experience with the prince of darkness and the magic smoke. Owned a tr6 and a tr7. The 6 worked great after I replaced the entire electrical system. I ultimately yanked the 6 and dropped a 327 and top loader into it. Was a mad thing after that. The 7 had serious electrical problems too. Wierdly the clock was the only part of it that didn’t malfunction regularly. Used to carry a can of contact cleaner around to cool down the ignition module when it overheated and caused to engine too quit. Eventually replaced the distributor with a cut up Acadian body welded up to the dolomite drive shaft. Used an msd module for the spark. Overheating problem went away. Sold it took my brother who was t-boned by an idiot who didn’t see him. Can’t imagine driving it today with all the brodozers.

      1. It’s the classic Man V Machine scenario and sometimes you win and sometimes you don’t!

        ( Some day’s you’re the bug and some day’s you’re the windshield! ) 🙂

  13. I’m a BMW fan, because I hate money, but yeah they are love / hate relationship cars. BTW I’ve had two E90s, a 328i wagon (N52 powered) and a 335i sedan (N55 powered that I still have). The supposedly good one (N52), broke way more than the supposedly less good one (N55). So even the “reliable” ones can throw you off.

  15. I feel your pain, Lewin. I had 3 of my four window regulators fail in my 97 540i6. Two of them within a week of each other. My wife’s 2002 Sentra? All four went the distance (well over 200k kms before trade in) without a single problem.

    The global auto industry knows how to build generic parts (like window regulators) that last, but for some reason the German carmakers can’t (or won’t) do it.

    1. Surprising since I used to have a 2002 Sentra for only like a year and a half and had to replace the driver’s window regulator and fuel pump (& previous owner replaced fuel pump too- they had problems w/ those)

  16. You know it is a bad day when you find your crankshaft pulley in the engine bay.

    I took my NA Miata to the dealer for its 60,000 mile service including a timing belt change. A few days later I was returning from the airport at night and the car just stopped running on the highway. I coasted to the shoulder and looked under the hood. In the plastic pan was the main drive pulley WITH THE END OF THE CRANKSHAFT STILL CONNECTED! Well that can’t be good. It seems the 1990 Miatas had a weak crankshaft end and the factory manual published the wrong torque setting for the crankshaft nut. The dealer and Mazda stood behind it so I got a 1991 longblock with the improved crankshaft for no charge.

    3. Subaru had a similar issue with the wrong torque spec for the EJ22 published everywhere but in the factory manuals and I had the same thing happen because of it after the first time I did a t-belt change, though I was lucky in that the pulley is what took most of the damage and the crank only had a small piece taken off the end of the keyway with plenty left intact. IIRC (which I’m probably not, but the point is the difference was large), the aftermarket spec was something like 85 lbs and the real one was 120.

  17. This is a failure item on some other random engines, from a combination of environmental conditions, age, etc..

    For instance, this happened to lots of old Ford CVH 4 cylinders on late 90s early 2000s Escorts/Focuses…even when they were only a few years old. They would make a hell of a noise when it would happen haha.

    Older 6.5 GM diesels had issues with the harmonic dampener too, although those issues would actually lead to catastrophic damage later on.

  19. This happened to my S4 last year. It also shredded both belts. I’m not really sure which one happened first. Thankfully the only sign was that it stuttered (once, under hard throttle) and was leaking coolant everywhere when I got home.

    The pulley was designed such that the loose piece was retained by the piece still bolted to the crankshaft.

    I ended up having to take the front of it off 3 times because the belts shredded a coolant pipe that was incredibly difficult to replace without destroying the O-ring sealing it.

    I really wanted to go one piece crank pulley after it happened but they stopped making aftermarket one piece ones that don’t overdrive the supercharger.

      1. It was a PITA but the only thing I learned from it is that I should buy a THIRD unreliable German car (backup for the backup)

        Luckily by both belts I mean accessory and supercharger, no timing equipment was harmed

  21. Oh yeah, these fail all the time on the diesels. We didn’t get the 4-cyl diesels here in the US, but the M57 straight 6 diesels blow their harmonic balancers constantly here. A friend of mine had an E70 X5 35D and he was stranded in the same way when his harmonic balancer failed. The funny thing is that he had already purchased the balancer months prior and was just too lazy to replace it.

      1. Hopefully your timing chain holds up… it’s at the back of the engine, so replacing it involves either dropping the motor or pulling the transmission and doing the job through the trans tunnel.

    1. yeah I think that’s the move
      my one concern is whether i can get the belt on with the existing tensioner

      normally you replace the tensioner and it has a pin to keep it out of the way until you’re ready for everything to tighten up

      1. I am not familiar with this specific case, but sometimes you can loosen the bolts on the idler and tensioner pulleys to help get the belt on and it is easier to tighten up the bolts on the pulley than hang harder on the tensioner lever (with the tool that barely fits the hole because there is no room in the engine bay). I probably should have replaced the pulleys when I did this last time, but only because they would have been like $20 a piece.

  23. Are there any timing related issues that should be addressed as well? You will already have the harmonic balancer/crack pulley off and that is the biggest hassle aside from access issues. Might as well do chain tensioners and such while in there (I’m assuming a diesel uses a timing chain and not a belt). Maybe throw on a water pump and belt tensioner as well. Seal it back up and run it. Once the front of the engine is opened up, just proactively replace all wear items to reduce headache later.

  24. > go for the N52B30

    …and then do a popular mod: buying and fitting a small metal shield to protect the front main crank seal. Why? So this doesn’t happen: (deep breath) the oil filter housing leaks oil onto the pulleys and the belt slips off, wraps around the crank pulley, and then bits of belt chew through the crank seal and start traveling around with the oil in your engine. Yet another Rube Goldberg failure mode from the engine-building geniuses at BMW.

    (Seriously, I love the engine, but the gotchas are bizarre.)

    1. This indeed one of the few gotchas with the N52. As my indy mechanic said, “Nothing goes wrong with these things except for the leaks.” Oil filter housing, valve cover, and oil pan are all common. You can pretty much let the valve cover and oil pan leak for as long as you can stand it, but if you don’t keep up with the oil filter housing, then you could suffer for it. (I don’t think the above is real common, but it happens.)

  25. For what it’s worth, my ’97 Jaguar XK8 threw a crankshaft pulley. It was, however, undamaged, requiring only a new giant bolt, a gallon of Loctite and a really large wrench to fix. Thus demonstrating the superiority of British engineering or something. On the other hand, I once had the plastic intake manifold blow apart, thus demonstrating that bad ideas are bad ideas no matter the nationality.

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