Short answer: yes, the B47 is significantly better than the N47 it replaced. BMW genuinely fixed most of what was wrong. But it isn’t bulletproof — we still see B47s coming through the workshop with stretched chains, just later in life and usually for predictable reasons. Here’s what we actually see on the ramps, and what to watch for if you own one.

Quick recap — the N47 problem

The N47 is the 2.0-litre four-cylinder diesel BMW built between 2007 and 2014, fitted to a vast number of 1, 3 and 5 Series cars, X1s, X3s and even a few MINIs. It earned a poor reputation almost entirely for one reason: the timing chain sits at the back of the engine, against the bulkhead, and the chain, guides and tensioner wear out far earlier than they should. Once the chain stretches, you get a diesel-like rattle on cold start, fault codes for cam-to-crank correlation, and eventually a snapped chain that bends valves and destroys the head.

The killer detail is access. Because the chain lives on the gearbox end of the block, the gearbox has to come out to do the job properly — a full day’s labour before anyone’s looked at a chain. The full story on the predecessor engine is in our BMW N47 timing chain problems guide.

What BMW changed in the B47

The B47 arrived in 2014 as the N47’s direct replacement and it’s still in production in updated form. It shares the same basic architecture — 2.0-litre, four-cylinder, common-rail diesel, rear-mounted chain — but BMW redesigned the chain drive almost from the ground up. The key changes:

• A noticeably stiffer, better-quality timing chain with stronger link plates
• A redesigned hydraulic tensioner that holds pressure more reliably as oil pressure fluctuates
• Improved plastic guide material that’s far more resistant to the brittleness and chipping we used to see on N47 guides
• Revisions to the oil feed in the chain area to keep the assembly better lubricated

What BMW didn’t change is the location. The chain is still bolted to the gearbox end of the block. So while the components are better, the labour involved in getting to them is identical.

B47D20 variants — O0, O1, U0, U1

You’ll see the B47 listed as B47D20O0, O1, U0 or U1 depending on year and application. The differences are evolutionary — emissions hardware, fuelling, software, mild internal updates — and from a chain perspective they all behave similarly. Later U1 units have benefited from the most refinement, but a well-looked-after early O0 is still a much safer bet than any N47.

You’ll find the B47 in 116d, 118d, 120d, 318d, 320d, some 330d variants, 420d, 520d, X1, X3, X4 and the MINI Cooper D.

Does the B47 still have timing chain issues in 2026?

Honest answer: yes, but the rate is dramatically lower than the N47, and failures happen much later. With an N47 we were routinely seeing chain stretch at 70,000 to 90,000 miles. With the B47, the cars we see with chain problems are typically beyond 120,000 miles, and there’s almost always a clear maintenance or usage reason behind it.

So if you’re asking “is the bmw b47 timing chain as bad as the N47?” — no, not even close. But “is it a sealed-for-life, never-think-about-it design?” — also no. It’s a wear item, and on a high-mileage diesel it eventually needs attention.

What causes B47 chain wear when it does happen?

When we strip a B47 with a stretched chain, the story is almost always one of these:

• Short-trip driving. School runs, supermarket trips, two miles to the station. The oil never gets fully up to temperature, fuel and moisture stay in suspension, and the oil loses its protective qualities long before the service light pretends it’s still fine.
• BMW’s longlife service intervals. The condition-based “up to 18,000 miles or two years” interval is, in our view, too long for a chain-driven diesel that’s worked hard. The chain assembly is one of the things that suffers.
• Chronic oil burning. If the car’s been topping up litres between services and nobody’s investigated why, the level may drop low enough between top-ups to starve the rear-mounted chain at exactly the wrong moment.
• Pattern oil filters. The bypass valve and filtration spec on cheap aftermarket filters varies wildly. We’ve opened up B47s where the oil was filthy at 8,000 miles because the filter wasn’t doing its job properly.

Cars that have been driven on long motorway runs, serviced every 10,000 miles with proper LL-04 oil and a genuine filter rarely give us chain trouble, even at high mileage.

Warning signs (same as N47, just later in life)

The symptoms are identical because the basic layout is the same. The classic giveaways:

• A distinctive rattle from the back of the engine on cold start that lasts a couple of seconds then fades
• That rattle gradually getting longer and louder over weeks and months
• Engine management light with fault codes 2A87, 2A86 or 2AAF — all relating to camshaft-to-crankshaft correlation being out of range
• A general roughness on idle, occasional misfires, or noticeably worse fuel economy
• In late-stage failures, the car going into limp mode or refusing to start

If any of that sounds familiar, don’t book it in for “a service to see if it goes away.” It won’t. Our guide on the signs of a failing timing chain covers what to listen for in more detail.

Is the repair any easier on the B47?

No, and there’s no honest way to dress that up. The gearbox still has to come out — no shortcut, no clever side access, no “we’ll just do it from the top.” Anyone telling you otherwise is guessing. The upside is that with better B47 components fitted, when we do the job it’ll last another high-mileage stint, not just paper over the cracks for two years.

The labour content is broadly comparable to the N47 — it’s still a big job — but it’s a fraction of the cost of a replacement engine, and a far better outcome than scrapping an otherwise tidy car. We’ve covered the wider pricing picture in our UK timing chain replacement cost guide, and our BMW timing chain repair service page explains exactly what’s included.

Should I buy a high-mileage B47?

Honestly, yes — with conditions. A B47 with a full BMW or independent specialist history, oil changed every 10,000 miles rather than stretched to the longlife maximum, is one of the better used diesel buys out there. We’ve seen these engines comfortably past 180,000 miles when looked after.

What we’d avoid: ex-fleet cars with patchy history, cars that have lived their whole life on five-mile trips, anything with an unresolved oil consumption note, and anything where the seller “doesn’t know” when the oil was last changed. Cold-start it before you hand over money — listen for any rattle from the bulkhead end of the engine and walk away if you hear it.

How to maximise B47 chain life

• Use genuine BMW LL-04 5W-30 oil — not a generic supermarket “fits BMW” alternative
• Change the oil and filter every 10,000 miles or annually, not at the 18,000-mile longlife limit
• Fit a genuine or top-tier OE-equivalent filter every time
• If most of your driving is short trips, take it for a proper 30-minute run once a fortnight to boil moisture out of the oil
• Cold-start with the windows down occasionally and just listen — you’ll catch a problem far earlier that way than waiting for a warning light
• If oil consumption creeps up, investigate it rather than just topping up

None of that is exotic. It’s just treating a hard-working diesel with the respect it needs to last.

Worried about your B47? Talk to us

If you’ve heard a rattle, picked up a 2A87 or 2A86 code, or you’re just thinking about a B47 purchase and want a second opinion, we’re a Sussex BMW chain specialist based in Copthorne (RH10 3LF), a few minutes from Gatwick. We do N47, N57 and B47 timing chains week in, week out, offer free collection within 15 miles, and back every job with a 12-month warranty.

Call us on 01342 643 780, grab a free estimate, or drop us a line through our contact page. Straight answers, no upsell — if your B47 doesn’t need a chain, we’ll tell you.