What Are Common BMW B47 Engine Problems?
Image: BMW B47C20B complete engine with 50K miles for sale at mtautoparts.com
BMW built its reputation on engines that feel right to drive. Strong mid-range pull, smooth cruising, and that sense that everything is working in harmony. When the BMW B47 engine arrived, it was meant to be exactly that kind of motor, a modern diesel that fixed the mistakes of the past and fitted perfectly into everyday BMW ownership.
For the most part, it succeeded. But if you live with a BMW B47 engine long enough, a few patterns start to emerge. Nothing dramatic, nothing headline-grabbing, just real-world issues that owners, garages, and breakers see again and again.
If you already own one, this will probably sound familiar. If you’re thinking of buying one, this is the stuff worth knowing before money changes hands.
First, what is the BMW B47 engine?
The BMW B47 is a 2.0-litre diesel engine introduced around 2014 to replace the N47. You’ll find it everywhere, from 1 and 3 Series models to X1, X3 and beyond. Variants like the B47D20A engine brought better refinement, better emissions control, and far fewer horror stories than its predecessor.
On the road, it feels exactly how a BMW diesel should:
Plenty of torque without working hard
Excellent fuel economy
Quiet and relaxed at motorway speeds
But modern diesels always come with trade-offs.
EGR problems: probably the most common issue
If there’s one thing that comes up most often with the BMW B47 engine, it’s the EGR system.
Over time, soot builds up inside the EGR valve and cooler. This is especially common on cars that spend most of their lives doing short trips, school runs, or stop-start commuting.
What owners usually notice:
Engine warning light
Slight hesitation or uneven idle
Reduced power in certain conditions
BMW addressed some of this with recalls, but even cars outside recall ranges can suffer. The key thing is timing; catch it early, and it’s usually manageable. Ignore it, and the problem tends to spread into intake and cooling components.
DPF issues on cars that never stretch their legs
This one isn’t unique to BMW, but the B47 is no exception.
Diesel Particulate Filters need heat to clean themselves. If the car never gets properly warm, the DPF never gets the chance to regenerate fully.
Typical symptoms:
DPF warning messages
Car feeling flat or sluggish
Fuel consumption is creeping up
Owners who mix city driving with regular motorway runs rarely have issues. Cars that only do short journeys almost always have problems, eventually.
Intake buildup and “it just doesn’t pull like it used to”
This is a slow burner. You don’t wake up one day with a fault light, you just notice the engine feels a bit lazier than it once did.
Carbon builds up in the intake over time due to EGR gases mixing with oil vapour. It’s not catastrophic, but it does affect airflow and response.
Most people only realise after a proper intake clean how much performance had quietly disappeared.
Timing chain worries (much rarer than people think)
Let’s address the elephant in the room.
Yes, BMW had serious timing chain problems in the past. That history still scares people, but the truth is, the B47 engine is a different story.
Timing chain issues do exist, but they’re:
Rare
Usually linked to poor servicing
Far less common than on the N47
If a B47 is serviced properly, chain problems are the exception, not the rule.
Fuel system and injector wear at higher mileage
As mileage climbs, injectors and high-pressure fuel components can start to show their age.
This usually presents as:
Hard starting
Rough idle when cold
A diesel knock that wasn’t there before
Fuel quality and service intervals matter here more than most owners realise. Left unchecked, injector problems can snowball quickly.
So… is the BMW B47 engine reliable?
Honestly? Yes.
The B47 isn’t perfect, but it’s one of BMW’s most reliable modern diesel engines. Most B47 engine problems aren’t internal failures; they’re emissions-related or maintenance-driven. If you pick a BMW with this engine, and your driving style is not suited, you might have problems. But…
Engines that:
Are serviced on time
Get regular long drives
Use good-quality oil and fuel
…tend to cover big mileages without any of these issues for a long time.
Buying advice (this matters more than mileage)
If you’re looking to buy a used BMW with a B47, or even looking for a B47 engine for sale, focus more on how the car was used.
Look for:
Strong service history
Evidence of recall work (especially EGR-related)
Smooth cold starts
No stored fault codes hiding in the background
A well-looked-after B47 with higher mileage is usually a safer bet than a low-mileage car that’s only ever done short trips.
Final thoughts
The BMW B47 engine does exactly what it was designed to do. It’s efficient, smooth, and genuinely enjoyable to live with. Most problems aren’t sudden failures; they’re gradual, predictable, and manageable if you know what to expect. That’s really the key takeaway. Understand how modern diesels work, drive them properly, maintain them sensibly and the B47 will reward you with years of solid, effortless driving.
Frequently Asked Questions
Is the BMW B47 engine actually reliable?
In real-world ownership, yes. The BMW B47 is generally regarded as one of BMW’s more dependable modern diesel engines. Most of the issues owners run into aren’t internal engine failures, they’re related to emissions systems or driving patterns. Look after it properly and it tends to behave itself.
What problems come up most often with the B47?
EGR-related issues are by far the most common. Over time, soot builds up in the EGR valve and cooler, particularly on cars that do a lot of short, stop-start driving. It’s rarely dramatic at first, but it’s something most long-term owners will encounter eventually.
Are DPF problems something to worry about?
Only if the car never gets a proper run. The B47’s DPF needs heat to do its job. Cars used mainly for short journeys are much more likely to struggle. Engines that see regular motorway driving tend to avoid serious DPF trouble altogether.
Should I still be worried about timing chains?
This is where the B47 gets unfairly judged. BMW’s earlier diesels gave the brand a bad reputation for timing chains, but the B47 is a different story. Problems do exist, but they’re rare and usually linked to poor servicing. On a well-maintained engine, timing chain issues are not common.
How long do BMW B47 engines last in practice?
There’s no single number, but many B47 engines comfortably pass 150,000 miles without major work. Those that are serviced on time and driven properly often go much further. Mileage on its own tells you very little; how the car was used matters far more.
Is the B47 suited to town driving?
It can cope, but it doesn’t thrive on it. Like most modern diesels, the B47 prefers a mix of driving. If it only ever sees short trips, problems such as EGR and DPF issues become far more likely over time.
What are the early signs of injector or fuel system wear?
Usually, cold-start issues, rough idle, or a diesel knock that wasn’t there before. These tend to show up as mileage increases. Fuel quality and service intervals play a bigger role here than many owners realise.
Does intake carbon buildup really affect performance?
Yes, but it creeps up slowly. Most owners don’t notice it happening until the engine starts to feel a bit flat. After a proper intake clean, the difference is often far more noticeable than expected.
Is a higher-mileage B47 a risky buy?
Not necessarily. In many cases, a higher-mileage car that’s been used properly and serviced regularly is a safer bet than a low-mileage car that’s only ever done short trips. History matters more than numbers on the dashboard.
What should I check before buying a BMW with a B47 engine?
Look for solid service history, evidence of recall work (especially EGR-related), smooth cold starts and no hidden fault codes. These tell you far more about the engine’s condition than mileage alone.
Are B47 engine problems expensive to fix?
They can be if they’re ignored. Most issues start small and are manageable when caught early. Left unchecked, they have a habit of turning into much larger bills than necessary.
Overall, is the BMW B47 a good engine to live with?
Yes. It does exactly what BMW intended it to do: deliver strong torque, excellent fuel economy and relaxed everyday driving. Understand how modern diesels work, maintain them sensibly, and the B47 is usually a very rewarding engine to own.
Disclaimer: This article is for general informational purposes only and is based on common ownership experience and workshop observations of the BMW B47 engine. Reliability and faults can vary depending on mileage, maintenance history, driving style and usage. Always seek advice from a qualified BMW specialist before making repair or purchasing decisions.
