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.
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.
Never quite seen one go like this before. pic.twitter.com/f8wssh3GjH
— Lewin S. Day (@rainbowdefault) January 31, 2024
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.
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.
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.
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