The Ford Bronco is pretty cool, a modern off-roader that really splits the difference between the cushy Land Rover Defender and lane-wandering Jeep Wrangler. However, some Broncos appear to have a fairly big problem. Dozens of owners are reporting spontaneous engine failure, often before the 5,000 mile mark. Let’s take a look at what’s going on.
First, some exposition. The engine in the Bronco isn’t actually anything new. Ford’s revised second-generation 2.7-liter Ecoboost turbocharged V6 first saw use in the F-150 pickup truck way back in 2018, so this isn’t some case of a brand new engine not having the kinks ironed out. Of equal importance, the second-generation 2.7-liter Ecoboost engine has developed a reputation for being fairly reliable. For example, manufacturer communications for 2018 F-150s with the 2.7-liter engine consists of two technical service bulletins for faults, one for a stall while towing that recommends powertrain control module reprogramming and another for an oxygen sensor-related fault. Minor annoyances, but nothing catastrophic. That’s all changed with the Bronco.
Taking a cursory glance at owners’ boards, it’s not hard to find tales of V6-equipped Broncos experiencing catastrophic engine failure. At the time of writing, 50 failures have been compiled by Bronco6G forum member Lucchese, with mileage ranging between 6,986 miles on the clock and just 984. A list of 48 owners one one forum with failed engines is pretty bad, but it gets worse — some of these owners have suffered multiple engine failures. Imagine how demoralizing repeat engine failure must feel, especially when you’ve spent tens of thousands of dollars on a brand new vehicle that should theoretically be fairly reliable.
R. Carson Mataxis understands the disappointment in Bronco engine failure. Eight days after picking up his brand new Bronco, its 2.7-liter turbocharged V6 died not with a bang, but with a whimper. “There were no loud sounds or shakes or anything. It was just a loss of power at the pedal. You’re pushing down a little harder and hoping for a response, but knowing something big was wrong,” said Mataxis. “I was in the left lane on cruise control, maybe going 65 or 70 (mph). I was able to navigate to the far right shoulder with about six inches between me and a guard rail, and maybe another 12 inches between me and traffic. The Bronco would shake every time an 18-wheeler passed.”
Breakdowns are never fun, but they can be properly harrowing depending on the circumstances. In Mataxis’ case, circumstances were almost as bad as they could get – more than 200 miles away from home in below-freezing weather with beloved pets on board. “The vehicle lost all power about 20 or 30 minutes into it, so it steadily got colder inside the vehicle,” said Mataxis. “I remember my toes were getting really cold. It was an inconvenience, that’s for sure, but it would’ve been so much worse if my two-year-old daughter was in the car.”
Ford would only tow Mataxis’ Bronco 35 miles or to the nearest Ford dealership. Not great when a breakdown happens on a Sunday when dealerships are closed. Mataxis ended up calling USAA for a tow, paying $713 out of pocket that he says Ford hasn’t made an attempt to make right. After just eight days of ownership, Mataxis’ Bronco suffered catastrophic engine failure requiring 32 days of downtime to correct. That’s just not acceptable performance from a new vehicle.
So what could be causing the Bronco’s V6 engine issues. Well, a January bulletin for Ford’s Lima engine plant has a tiny little note that says, “Nano valve supplier issue was resolved with more robust design and material changes at the supplier.” Nano is Ford’s codename for the 2.7-liter V6, so there’s a strong possibility that a valvetrain issue is at play here. Indeed, the National Highway Traffic Safety Administration suspects just that. This NHTSA investigation document claims valvetrain failure as the cause, likely due to diagnoses on complainant-owned vehicles. FordAuthority claims that in addition to faulty valves, Broncos equipped with the 2.7-liter V6 suffer from a bad oil pan design that may let the oil pickup tube suck in air. Oil is kind of like the blood of an engine, so imagine if suddenly an air bubble appeared in your bloodstream. You’d just sort of die, and it’s the same deal with an engine receiving air instead of oil.
When an engine drops a valve without any catastrophic event like a money shift happening, a few failures could happen. A brittle valve could fracture where the valve meets the stem or an improperly-machined valve could let valve keepers come loose. Another scenario is that a variable valve timing issue could try and force the valve to occupy the same space as the piston on an interference engine. Whatever the case, the outcome is similar. The fast-moving valves bash against the fast-moving piston, tearing each other to absolute shreds and potentially taking out the connecting rod on the way down to the oil pan. Because the engine loses compression on one cylinder as soon as the dropped valve stops sealing, it usually runs incredibly poorly as that cylinder is unable to do its job. Modern engine management systems will often detect this severe misfire, go into a failsafe mode and shut down power, echoing the failure experience reported by Mataxis and others.
So how many Broncos might be affected? Well, the NHTSA’s narrowed down the number of potentially affected units to 25,538 from the 2021 model year, which seems like a lot considering Ford sold 35,023 Broncos in 2021. According to the Bronco6G forum, 2022 models weren’t actually delivered until the first quarter of 2022, which leaves 72.9 percent of all 2021 Broncos potentially affected.
Right, enough numbers for now, let’s get to the carnage. There’s a perverse fascination that comes with looking at failed engines, and that’s still the case here. Someone posted a TikTok of a 2.7-powered Bronco with what looks like the aftermath of Robocop’s bachelor party at the bottom of the oil pan. Take a look at those chunks. Bronco6G forum member North7 has kindly annotated a screengrab of the oil pan, perfect for dissecting exactly what we’re looking at. It looks like we’re seeing some nice chunks of piston and connecting rod, along with what appears to possibly be a dropped valve. It’s a bit tough to tell on that last one as everything in the oil pan has been mashed into absolute bits, but there’s definitely a certain silhouette going on.
Bronco Nation user KennyMac also has an interesting pic of bits of a piston not being where they should. Yeah, it’s generally not good news when an engine’s like “I hereby pronounce you piston and valve, you may now kiss the valve.” Honestly, I bet that this connecting rod would’ve made a hell of a racket bashing against the cylinder walls. It’s also worth noting that several engines have chunks missing from the spark plug on the affected cylinder, the sort of thing you’d expect to see after chunks of metal bash their way around the cylinder. Although it’s possible that this Bronco issue is isolated to a particular batch of valves installed in a batch of engines shipped to Ford’s Michigan Assembly Plant, the true scope of the issue isn’t really known at this point. While there’s a chance everything will work its way through the warranty system, it might take a while.
See, we’ve only seen low-mileage engine failures so far. There’s definitely a chance that more failures will arise as Bronco owners pile miles on their V6-equipped rigs over the coming months. What’s more, Broncos might not be the only vehicle affected. See, while the Bronco was the first Ford to get the latest variant of the 2.7-liter V6, that engine can also be found in the F-150. While the F-150 is a much more mass-market vehicle so owners likely won’t be as loud about failures, reports of seized F-150 engines aren’t exactly nonexistent. This post on f150ecoboost.net details a familiar failure pattern – low mileage, unexpectedly failed engine that simply shut off.
Top tip, if you or anyone you know has experienced a major vehicle defect like sudden engine failure on a V6 Bronco, let the NHTSA know. You can get in touch with them by clicking this link, reporting a problem takes about as much time as ordering a pizza, and doing so could result in actual action.
It should go without saying that, if these reports prove accurate, brand new vehicles shouldn’t be experiencing rapid unplanned engine disassembly, and I’m saying that as someone with an affinity for German shitboxes who’ll brush aside V10 M5 rod bearing replacement as maintenance. It doesn’t help that between parts shortages and scarcity of both rental and loaner cars, engine replacement on a new car sounds like hell right now. Then there’s the possibility of trip interruption. What if you’re hundreds of miles from home when the engine in your new car goes pop? Your car could be stuck away from home for weeks waiting on parts. It’s going to be interesting to watch this defect investigation play out. Hopefully Bronco owners get an actual proactive solution rather than engine replacement after it blows. It’s typically much easier to prevent a disaster than to clean up after one.
[Editor’s Note: We temporarily un-published this post to remove an image of the wrong engine; we’d also like to note that for various reasons we haven’t been able to directly secure photos of owners’ failed engines, mostly due to dealer communication protocols, according to the author. If we are able to get confirmed images of the aftermath of one of these reported failures, we will update the post. – JT]
I want to understand 1 thing:
In all the years Ive known about people buying cars and for all the years that various cars have been sold… why is it that common sense says.. dont buy a first year car (every car has bugs of SOME KIND). So ya wait till the next or 3rd to pick one up.. knowing the issues are dealt with by then…
Why in the world.. is everyone going gung-fucking-ho on all these new damn cars, then crying when they dont live up to the standards.. they set for the vehicles??
” a variable valve timing issue could try and force the valve to occupy the same space as the piston on an interference engine”
I’m pretty sure you have this one wrong(?).
A VVT system still has camshafts ,and those *shouldn’t* allow the parts to meet,at all,ever. A faulty VVT system will merely screw up the power curve*.
That said it is possible to design a system that adds lift above and beyond what the cams provide.Extendable hydraulic lifters are one way, but there are other methods available.
I’d be super curious whether any manufacturer has ever gone that route. It would be a super risky strategy given that an electronics fault would ruin the engine
*If you ever get the chance ,disable the low-speed setting of VVT.The results are hilarious! All top end with no power anywhere else.
It’s even funnier on a 125cc motocross bike!
Just wondering here. With all these poorly built crap Broncos, hopefully DT blows up one on his test drive, if they have to do a buyback do they get reimbursed for the 10 thousand dollars premium they paid? Who covers it Ford or the scummy dealer?
They should want everyone to stop driving. Even if it hasn’t exploded yet, they should be swapping heads on every single one since a head swap with a good core is infinitely cheaper than an entire engine swap with the block and pistons and rods and heads being junk. It wouldn’t cost that much to seed like, 500 sets of heads with known good valves and just start swapping heads, then refurb the heads that come off and put them back onto the others that come in.
Our 2022 Kia Telluride with only 1485 on the clock is currently in the shop (had to be towed there). They say it’s an injector but I don’t ever remember fuel problems smelling like metal on metal….
Failure Of Research & Development
What happened to just keeping what works on the road? I had a 4.6 make it past 500k before it developed a light rid knock…was still running when pulled. Or another 4.6 that I put over 100k on a blown head gasket? Luckily it was exhaust side but still…chugging along.
Why not keep what works in service? Upgrade it…hell lop 2 cylinders off like they used to and make a V6?
I only own older pre 2003 vehicles except my fiance’s 2017 Corolla WHICH has a dash full of lights that the dealer can’t figure out at less than 80k! But my 03 Excursion starts up after months without slipping a beat and STILL has no dash warning lights on.
New stuff is PATHETIC
Because the 4.6 in most trims only made about 230hp, and with reliable 4 bangers making 300+ now, they’d be roasted endlessly in marketing and the press for having 100 less hp than competitors. But also, gas prices may go back down at some point, but they’re never going back to $2-2.50 a gallon again in the US. Prices were already 3x that in most of the rest of the world anyway. And you want to stick with things that get 13mpg going downhill with a strong tail wind? This issue was simply caused by manufacturing errors. There’s nothing wrong with the design as evidenced by it NOT happening on any other vehicles with this engine over the past 4-5 years. This isn’t a Fiero dripping oil onto the exhaust manifold and catching fire design flaw, this was ‘a supplier fucked up and didn’t make these the right way.’ situation.
Because the 4.6 makes horrible power and gets even worse mileage. Put a bad batch of valves in the 4.6 and you’ll have the exact same issue.
You can make new, fancy engines reliable, but you have to make sure your design is bulletproof (how about using a metal oil pan once in a while, Ford?) and your suppliers are on point (which seems to be the issue here).
You can’t make money on stuff that lasts.
All Broncos with the 2.7L should be recalled. If the engine hasn’t let go, replace the valves or have cylinder head assemblies ready to go. The oil pan? Get that right and put new ones in. It sucks that the valve supplier screwed up so badly, but a Bronco done right prints money. Jeeps suck, but they have such loyalty behind them that sins are forgiven. Ford needs to show that they aggressively are fixing Bronco birthing pains (and lord, that’s a hefty truck to give birth to!)
oooofta those pictures make me nauseous. Such a shame because the Bronco is an achingly cool vehicle.
In the old days, when I worked for one of the other “big three,” every so often an engine and transmission was pulled off the build line and run on a programmed dyno life cycle test by the reliability test group, then torn down and carefully examined. Intended to prevent this kind of $$$ quality problem from getting into too many finished cars. Wonder if Ford does that?
Big 3 quality engineer here. We still do that
Reading that letter from the Lima plant, it really sounds like a new valve supplier/design was introduced and they got the material or heat treatment wrong.
The valves are probably too brittle with the failures happening with low mileage.
The Bronco should have been offered with the ultra reliable 6.2L V8 from the beginning.
Maybe the 7.3 if you really twist my arm.
That’s because they’re only meant to go 3 mph in a police chase 😛
And I thought “Found On Road Dead” was a thing of the past. It will be interesting to learn if this turns out to be an engineering problem or an accounting problem (“let’s shave a few pennies here, you don’t really need a fancy oil pan like that”)
It’s so disheartening. Your brand new car blows up and you’re treated no better than someone with a ten year old car that needs a new alternator. “Thanks for spending $40,000 with us. Park it over there. We’ll call you when it’s ready. We don’t know when.”
I guess add “randomly exploding engines” to the list of reasons I want a brand new car less and less each year.
Even worse, since an alternator can be replaced in about an hour and the parts are available right now, or we can have it tomorrow. A new motor is 10’s of hours of labor, $1000’s in parts that the dealer may get reimbursed for but they’re still gonna fight you about it, plus I HIGHLY doubt that there’s going to be enough engines in inventory to get them where they need to go in a timely manner, ESPECIALLY considering they have to be freighted.
I’d hate to be the dude who paid over MSRP for the truck only to have the engine grenade a short time later. Big oof.
Is it me (Kia owner) or do “complete engine failures” seem to be more common these days? Kia/Hyundai, Honda (maybe), Ford, maybe others have all had well-publicized complete engine failure issues. Are they getting too complex? Is something happening with QC? Is it a pandemic-induced workflow-cluster-fuck issue at the plants?
I’ve kinda wondered the same thing, and I think you may be onto something with the complexity angle.
The endless quest for better fuel economy, lower emissions, badassness in everyday driving may be pushing things into unsustainable territory maybe? And people are accustomed to having everything they want at once (e.g. gone are the days when woefully underpowered was accepted by the public as a trade-off when buying an everyday commuter car) at this point.
Wonder if it’ll be like this until EVs become dominant. Like how in the waning years of carburetors, they just kept getting more and more complex to meet various requirements, as fuel injection increasingly solved the problem in a more reliable and simpler manner.
What complexity the Germans have been doing this for decades. You never here them complaining.
Apparently qualified experts from Germany were far easier to get after WWII were easier to get with the threat of war crimes prosecution than just hiring them with relocation to a place with better food and women who shave everything.
Things that make you say Hmmmm.
I think it has a lot to do with higher compression ratios, extended oil change intervals, turbos (on some cars) and heavier cars overall. Smaller engines going into heavier cars. They’re overstressed compared to the gigantic V8s of yesteryear.
I’ve often heard that the downside of being able to engineer things more precisely than in the past has meant operating margins have been considerably designed out.
We probably are more acutely aware of these issues than in the past due to the increased visibility that comes with forums and such
I remember hearing this regarding the BMW E36 versus the E30, like twenty years ago. It probably remains true.
Under 5K miles?
I bought an early Fr-S when they came out and that engine popped at around 40k miles. Not much drama, but complete failure. I didn’t get the details of the failure from the dealership (other than it requiring a full engine replacement), but from the way it spun freely from the starter it seemed like it had lost all compression.
They took care of it (I’m pretty sure I saw some priced internal paperwork showing the cost of the job as $18,000 or so. With the other recalls performed, that didn’t leave much or any profit versus the purchase price.
The biggest hassle was the time it took. I was in a loaner car for a month. It seems like that’s the standard time for a dealership engine replacement. Maybe engineers need to stop working on swappable battery packs for EVs and focus on quick-change internal combustion engines.
The few i’ve heard about disintegrated with lowish miles on board,so something’s up.
I’m guessing the manufacturers noticed their engines are lasting waaaay past a car’s average lifespan and so felt ok cutting a few corners?
i.e. probably a bean counter’s decision
There have always been bad motors and bad parts batches here and there. For all the complaints about complexity introduced for emissions and efficiency, I don’t think overall engine reliability and longevity has gotten worse. If anything, it’s improved.
The recent batch of failures can probably be traced to pandemic-related issues. Corner cutting due to staffing issues, lowered QC thresholds on parts because they’re in too short of supply to reject them, emergency part/vendor substitution with inadequate vetting. Cars built in 2020-2022 are going to get a skeptical eye for years to come.
I believe those issues were related to the Turbos being blown.
Everyone err all the automakers have this 1.(sneezes) motor and they team it with this (sneezes hard) hair dryer of a turbo and the thing blows cause its overworked.
I’ve heard of shutting down cylinders at highway speed, but this is a bit extreme.
Now they can tout “parked at the dealership service department” as a fuel saving feature for the Bronco.
The hits just keep rolling for the spotless Bronco launch. Oh wait, maybe not so spotless.
I guess its a Ford thing, they replaced the whole engine for my 2019 Ford Escape with the 1.5T, head gasket failure, coolant got into the engine block and white smoke coming out of it like crazy. GM products may disintegrate while you drive but their engines keep pushing hard
Yeah I’ve owned almost nothing but VW/Audi from 1990 until about 2012. Lots of stuff broke, but they never broke down or left me stranded other than a starter died on my ’90 Corrado in 2001 with 100K miles on it. I never had a problem with the super charger, either. Mainly because the service manual said you need to have it serviced every 30K miles, so I did. All the ‘garbage unreliable explodey ones’ people were like ‘well, yeah it’s got 58K miles on it and I never serviced it, but it’s a piece of crap!’
Cmon everything in the auto manufacturers world nowadays is designed to do just a speck above what it NEEDS to do. Mo oversight often leads to it can’t even do that. Reference US car manufacturers in the 70s. Those who don’t learn from history are bound the repeat it.
KennyMac’s picture is definitely not of a Bronco mill. There are pushrods and more than 3-cylinders in a line so there’s no way it’s the 2.7 V6 in-question. If I didn’t know any better, I might say it’s actually a 4.0 Jeep engine. If only there was somebody around here that’s familiar with those things… 😉
If you click the link, you can see the KennyMac picture. The imbedded photo definitely has a whole different vibe.
Based on the piston’s it’s a 4 valve motor so not a 4.0, but your right certainly it’s no V6
They fixed it. The original imbedded photo was a still image of a different (rusty) engine. You could see at least 4 pistons in a line. Probably from a David Tracy article.
Pretty sure that is just Fords new advanced cylinder deactivation.
Permanent deactivation
It helps reduce emissions too.
I dunno about >reduced< emissions: looks to me like those motors are emoting the living hell out of valves & stuff
Valves, pistons, rods, and block chunks are non-regulated emissions. Criteria pollutants are way down. Gotta be careful playing that game though, or the next EPA reg will limit you to no more than 0.1 valve per mile emissions.
Yep, it deactivates all of them.