My Diabolical BMW Is Trying Its Hardest To Bankrupt Me

Early last month, I declared victory against my wife’s stately 2001 BMW 525iT E39 wagon. The Beemer, which seemed to be on death’s door with absurd oil consumption, catastrophic misfiring, and impressive smoke, was fixed with $400 of parts and labor plus a so-called “Italian Tune-Up.” The car was now better than ever, but it’s not lasting. Just 3,000 miles later the car has found new and creative ways to break. Here we go again, is this thing haunted?

Back in late 2022, our secret designer The Bishop sold me this stately wagon. At the time, it had just minor issues. The car needed a new catalytic converter, new tailgate wiring, and rust repair, but that was it. I drove the wagon for some time before I gave the vehicle to my wife as a gift. This car has changed her life. Sheryl has always been the kind of person to exhaust seemingly infinite energy to help others, but little for herself. So, she’d drive things like base model Subaru Imprezas and Toyota Camrys, never realizing that driving could be thrilling.

The Bishop’s E39 changed that. This was a car that, at the time, was both reliable and thrilling to drive. Sheryl traded cloth for leather, an inline four for a straight six, and a Toyota badge for the BMW roundel. The BMW might be the greatest automotive evolutionary step my wife has experienced. It may be a $1,500 pile of German over-complication to you and me, but it means the world to her.

So, we’re continuing to keep this car alive, even when it seemingly wants to take a nap.

What Broke Last Time

My wife drives a lot. As of now, she’s on track to drive a tick over 40,000 miles this year. She drives more than I do, and I’m the one who writes about vehicles! Sheryl is often ripping across the state of Illinois to show up in courts all over these flat lands. Unfortunately, this puts a lot of wear and tear on a vehicle and she doesn’t have the time for a car to be broken for too long.

According to our calculations, Sheryl drove the BMW about 30,000 miles in a little less than a year. That’s a lot for any car, let alone a 23-year-old, well-loved German car. At first, things were great. She installed new coils and plugs, gave the car a full brake job, and vanquished the infamous “trifecta” ABS, traction control, and brake warning lights in the instrument cluster. That last one felt particularly good because not even the Bishop was able to fix that. We even diagnosed the vehicle’s airbag light to be a faulty mat in the passenger seat.

Sheryl then went on to add individual touches to the car including interior trim imported from Germany, new headlights, and modern infotainment. The Beemer purred like a kitten and even scored 30 mpg. Then things got bad:

Then late October rolled around and something changed about the car. Suddenly, fuel economy went into the toilet and oil consumption was best described as epic. I measured oil burn to be as much as a quart every 50 miles. My mechanic friends and even readers here suggested that there could have been a blown head gasket. But the car’s fluids never mixed and aside from the oil, they never changed their levels either. Yet the thick clouds of oily smoke billowing out of the tailpipe suggested the car was using oil worse than a two-stroke motorcycle.

By November, things started getting dire as the M54 2.5 six signaled its displeasure with its existence and stopped running on one, sometimes two of its six cylinders. The misfires were constant and shook the car harder than a Harley-Davidson’s V-twin. From November forward, there was never a time when the car didn’t misfire.

The problems made the car, named Wanda, undrivable. An oil consumption of a quart every 50 miles makes driving to downstate Illinois prohibitively expensive. That’s ignoring the fact that the car ran on five cylinders on a good day. Sheryl ended up parking Wanda and it sat for months. Every time we started Wanda, it groaned into life with a smoke show and a flashing check engine light. Our mechanic friends gave us scary potential causes from piston rings to possible top end trouble. Everything looked hilariously expensive for a car I spent just $1,500 on.

In April, Sheryl was ready to throw in the towel. She sent me out to take pictures of Wanda for a listing and in typical me fashion, I welded the accelerator to the floor. Eventually, the car cleared its throat and the misfires were gone. Even the smoke let up a little bit.

This gave her the motivation to get a third opinion on the smoke. I rang up my friendly mobile mechanic and one day he replaced the vehicle’s crankcase ventilation valve. It was an instant fix, with not a puff of smoke coming out of the exhaust. Oil consumption then returned back to its normal of a quart every 1,200 miles or so. The best part is that parts and labor were just $400. We then replaced the car’s catalytic converters, which turned off the check engine light, seemingly for good. The Bishop told me the instrument cluster hasn’t been that devoid of warning lights in over a decade.

That sounds like a mission success in my book.

It’s Gone To Hell, Again

Sheryl’s been driving her beloved Wanda through May and things were great for most of the month. The car didn’t smoke, didn’t burn any abnormal amounts of oil, and didn’t misfire a single time. My wife had her baby back. Of course, because old German cars like to be silly, we’re now in a situation that seems both strangely familiar and new. Sheryl’s put just 2,500 to 3,000 miles on this car since we fixed it.

The first sign of new trouble came when I was following Sheryl home with the Can-Am Ryker press loaner. Sheryl hit the gas on a green light and a little puff of oily smoke came out. Uh oh. Still, that wasn’t so bad, it was just a puff! Then, Sheryl let off the accelerator to turn a corner. As the vehicle turned right, a cloud of smoke emitted from the tailpipe. Now, Sheryl says it’s back to smoking constantly. Crap.

The car then had to get cute. One day, we were just relaxing at home when the car’s alarm started sounding. A check of my security camera showed nothing bothering the vehicle. It just started crying all on its own. That was weird, but we decided to keep on trucking. It got worse quickly. We’re now to the point that the car will sound its alarm less than an hour after the vehicle is locked. Thankfully, Sheryl now has a garage, so the car can be left unlocked at home.

At first, I assumed the issue was the rusty tailgate’s latch sensor failing. Sometimes the vehicle thinks the tailgate is being opened even though it’s closed. My Volkswagen Touareg VR6 had an issue similar to that. A deep scan of the vehicle shows a single immobilizer code of “0F – Power-On Reset.” That’s an error caused by low voltage. The battery died recently so that one makes sense. I cleared it and as of publishing it didn’t come back. One error is stored in the body control module with “5E – Central-Locking Drive, Passenger’s Door.” Some early research suggests this could be a potential wiring issue or a lock actuator issue. The failure mode seems non-functional central-locking on that door, not the alarm sounding. Either way, the locks are working great right now.

Sheryl has also noted that on one recent occasion, the vehicle shut down while she was driving. The engine stopped running and the electrics went dark while she was moving. Turning the key to the off position and then turning the vehicle back on resolved the issue. I have not been able to replicate this.

The misfiring came back, too, but this time it’s intermittent and seemingly random. Punching the throttle doesn’t seem to make a difference. Wanda is now back in the garage far sooner than expected. Sheryl feels she cannot trust the car at this current time, so I have to bring it back…again.

Now it’s time for me to roll up my sleeves.

What’s Next

First, I want to tackle the misfire. I know Sheryl is using some pretty “sus” aftermarket coil packs and white-label spark plugs. Thankfully, I keep old working parts for troubleshooting purposes, so the Bosch stuff will go back in for now. Of course, I’ll inspect the plugs upon their exit as well. My mobile mechanic said that the car is in dire need of new vacuum lines, so those will need to be replaced, too. I’m fairly confident I can knock out the misfiring issue.

I think I can tackle that alarm system, too. Some E39 owners have had issues with their alarm systems going off after a failure of the hood sensor. Like all good German cars, the E39 is also said to be sensitive to battery voltage, so we should test and maybe replace that battery since it died once. I just have to inspect the alarm system. If we’re lucky, it’s just the hood sensor and that can be disabled.

I’m less sure about everything else.

The smoke is a curious one. Why did the car drive for a whole month without smoking? What could have happened? I suppose there is a non-zero chance the new CCV already failed, but that would be weird. It’s also notable that the smoke isn’t as heavy as it was before. The smoke before was dark blue, almost black. This stuff is a lot lighter. Still has that pungent oil smell, but it’s not the same. Oil burn has increased to a quart every 500 to 600 miles. Past experience would suggest possible valve seals as a culprit, but I’m not certain.

I also believe Sheryl when she says the car shut down while she was driving. The question then becomes why? Apparently, the ignitions in these cars can fail, which could cause this. But I want to replicate this before shooting in the dark.

Either way, I have a feeling I’m going to be spending much of this summer tinkering on Wanda. On one hand, it’s frustrating that this car just keeps finding dumb and annoying ways to break. On the other, I am learning a lot about BMWs during this process! Hopefully, we’ll eventually get back to a place where the car can be trusted to go anywhere at a moment’s notice. At the very least, Sheryl’s Scion iQ is still a champ that isn’t letting us down. Thankfully she has a reliable daily driver or else I’d be sweating bullets.

If any of our lovely readers are more well-versed in BMW than I am, I want to reach out for your help. What am I missing? Do you have advice here? Well, advice that isn’t “sell the car,” that is.