Few marques command as much respect from people who crave performance as BMW, and the M line of cars in particular are some of the most desirable and most powerful vehicles around. However, there’s a closely guarded secret that no respected publication would ever broach, and it’s that all BMW engines are monumental piles of unreliable garbage.
It’s no secret that German reliability is a myth. The likelihood of an average German car making it 10 years without several unplanned roadside mishaps approaches the same probability of you waking up tomorrow as Katy Perry.
Before I get several angry, slur-laden, and poorly-spelled emails from bimmer bros that need to prove that their 130,000 mile, salvage-title 335xi with the M-tech package is just as reliable as it was when they first decided to finance it for 96 months from their uncle’s buy-here-pay-here-lot, let me give you a little much-needed perspective.
Over the last few years, I’ve bought and sold some of BMW’s most desirable consumer cars. I’ve owned them, driven them, and most importantly, worked on them - five in total, ranging from the arguably benign E36 M3 to the staple of performance that is the E39 M5.
Without any hint of sarcasm or hyperbole, I can tell you that every single time I started any engine with a BMW badge on it, there was the same sense of concerned dread that the stereotypical bomb squad guys got in ‘80s action flicks. Starting and running a high-strung BMW engine that’s destined for daily driver duty without incident is like finding a briefcase with a big red LCD display with five seconds left, with the choice of cutting the red wire or the blue wire, as a sweating Danny Glover somewhere in the background tells you that he’s too old for this shit. It’s a literal time bomb.
Let’s take, for example, my old E36 M3. It featured a US-only spec 3.2 liter straight six cylinder engine that produced around 240 horsepower. It also had a unique problem in which the nut that held the sprocket driving the oil pump would fall off. Yes, the one thing that made sure your engine was oiled properly would simply fall apart, because it wasn’t torqued down properly from the factory.
If this part went, as it was apt to do over time, your engine, maligned by some as the worst M3 engine ever made, would be considered a prime candidate for the deadest M3 engine ever made, as the insides would turn themselves to confetti in short order. This wasn’t so much as a defect as it was a promise, a race against the clock that would net you one hell of a story to tell your friends as you cry into your already tear-soaked repair bill.
And that’s the reliable one.
If you move to more late model stuff, the situation gets a bit more dire. Let’s take the E46 M3, for example. It featured a 333-horsepower naturally aspirated inline six cylinder engine that was more unreliable than an AA meeting sponsored by Miller Lite. These engines were were plagued with connecting rod bearing failures, issues with the variable cam timing (VANOS), crankcase ventilation failures, hard starting, and their cooling systems were made of plastic and sealed, ensuring catastrophic failure where scalding hot coolant would shoot out of your engine bay, overheating your engine, at which point your head gasket would blow.
The same goes for every M-branded car that BMW has made in the last decade, and these problems are well-documented. The E60 M5's V10 will chew through its rod bearings in less than 60,000 miles and has rampant and costly SMG pump failures. The E92 M3 will also devour its rod bearings in short order. The new M3 and M4 engines have crank hub failures that take the engine out of sync and smash the valves into the pistons. They also suffer from oil cooler issues, in which overheating is a valid concern, especially if you’re the kind of person that drives your car like the PR reps claim you can around a track.
“Ah yes, but those are only the special, performance-only versions of engines BMW makes! The regular ones are the ones you want,” you type while the oil puddle underneath your car drips its way into the Earth one millimeter at a time. Sorry, but not quite.
For example, the E39 540i had timing chain guides made of melted jellybeans that would literally start disintegrating as soon as you even thought about the concept of an expired warranty, leaving a potentially huge chunky mess at the bottom of your oil pan, but that wouldn’t matter, as your oil pump mounting bolts would work themselves out way before that ever occurred. The engine would reduce itself from a taut, muscular bellow to a feeble, rattly, barely-running mess in about 120,000 miles, and that’s unacceptable for a $5000 Craigslist beater, much less a near-$60,000-when-new luxury performance sedan.
That’s exactly why I sold mine for a massive loss and couldn’t have been happier to get rid of the problematic nuisance.
The earlier inline-six cylinders featured in the 3 and 5 series cars also suffered from a brittle cooling system that would spring leaks and rupture without any advance notice, cooking up a recipe that ended with a blown head gasket and a classified listing that reads: “runs good, needs engine.”
Going further down the hierarchy, the relatively new N20-series engines that featured four cylinders and turbochargers experienced timing chain stretching that necessitated two weeks’ downtime and a new engine. Not the end of the world with a warranty, but bank account destroying if you’re one mile out of the safe zone.
At the very top of the non-performance totem pole is the 7 Series, a car known for shitting its valve guide seals. Though I wrote an explainer on how to fix the issue, the fact remains that these problems shouldn’t happen from a manufacturer that advertises its cars as “The Ultimate Driving Machine.”
If my anecdotes and forum sleuthing doesn’t persuade you, perhaps you can compare the aggregated long-term reliability of, say, any BMW model made in the last 20 years with that of a regular, boring-ass Toyota Corolla. The Bimmer consistently scores 20-30 points less than any comparable econobox, warranty or not.
At this point, I, as well as anyone with two brain cells to rub together, should be completely turned off to the idea of realistically owning a BMW if it has anything close to its original engine living in the bay. They may perform well for a period of time, but the very real risk of catastrophic failure on any or all of the internal components in these particular engines is enough to let anyone in the used car market stay the hell away.