BMW B47 Rebuild, common faults & everything you need to know
A complete guide to BMW's modern 2.0 diesel - the successor to the N47 in the modular engine family (sharing architecture with the B37/B38/B48/B58). A common-rail inline-four with DOHC, 16 valves and a single or sequential twin-turbo. From the timing chain, EGR cooler and swirl flaps to power builds, with workshop pricing and clear common-problem guides.
We have built and rebuilt BMW turbodiesels for decades. The B47 is the N47's successor and is found in virtually the whole of BMW's modern diesel range - the 1, 2, 3, 4 and 5 Series plus the X1, X2, X3, X4 and X5, as well as the MINI Cooper SD. It is a common-rail inline-four with DOHC, 16 valves and an aluminium block, in single-turbo or sequential twin-turbo form depending on power level. The B47 kept the timing chain in the same rear position as the N47, but with a substantially reinforced chain, more robust guide rails and better oil supply - which means timing chain failures are far less common and come much later in the engine's life. The engine does, however, share the international EGR cooler recall with the N47 and N57 (coolant that can leak into the intake). We do everything from cylinder head reconditioning and turbo reconditioning to complete engine reconditioning with our own machine shop and a 12-month warranty.
The B47 at a glance
Shared base data for the B47D20 family (BMW's modular inline-four diesel, sharing block and piston architecture with the B37/B38/B48/B58). Variant-specific power and torque figures are listed in the table below, cross-verified against at least two independent sources per value.
| Power | Forced induction | Torque | Typical example | From year |
|---|---|---|---|---|
| 116 hk | Single VGT | 270 Nm | 316d | 2015 |
| 150 hk | Single VGT | 320-360 Nm | 118d / 320d | 2014 |
| 190 hk | Single VGT | 400 Nm | 120d / 320d / MINI Cooper SD | 2014 |
| 224 hk Twin-turbo | Sequential twin-turbo | 450 Nm | 125d / 225d / 325d / 425d | 2015 |
| 231 hk Twin-turbo | Sequential twin-turbo | 450-500 Nm | 525d / X1 xDrive25d / X2 / X5 | 2015 |
The power and torque figures above are identity data (the engine's output, not tightening torques), cross-verified against Wikipedia and independent spec databases (mymotorlist, torquecars). The "TU1" power update (November 2017) raised the injection pressure and extended the twin-turbo to more variants, but gave no power increase on the most common 18d/20d engines - the focus was on emissions and efficiency. Since November 2019 there has also been a 48V mild-hybrid version with an electric boost.
Torque specs
We only publish torque specs we have been able to verify against an actual factory page. For the B47 we have not yet completed that verification against BMW TIS (the same process that produced the N47's factory-verified tables). We never guess and never borrow another engine's values. If you need tightening torques for your own job, get in touch and we will source them from the correct factory manual before your job begins.
Common problems on the BMW B47
This is what we see most often when a B47 comes in. Symptoms, causes and how we fix them.
EGR cooler - coolant into the intake
Shared recall with the N47/N57 • Critical- Symptoms
- A dropping coolant level with no visible external leak, white smoke from the exhaust and, in the worst case, soot deposits in the intake manifold that ignite from high exhaust temperatures.
- Cause
- The cooling fins inside the EGR cooler crack over time, letting coolant into the exhaust flow where it mixes with soot. The fault was originally identified on the N47/N57 but led to an extended international recall that also covers the B47. We check and replace the EGR cooler in connection with larger engine work.
Timing chain & guide rails (rare, late in life)
Uncommon compared with the N47 • Medium- Symptoms
- A rattling noise from the rear of the engine on cold start. Because the B47 is an interference engine, the result is bent valves if the chain jumps or breaks.
- Cause
- BMW kept the timing chain's rear position from the N47, but reinforced the chain with heavier-duty links, more robust guide rails in a more durable plastic material, a redesigned tensioner and better oil supply to the chain area. As a result, failures are far less common and come much later in the engine's life, strongly linked to neglected oil changes rather than a fundamental design that fails on its own. Because the chain still sits at the rear, the engine and gearbox must be separated to replace it.
Swirl flaps in the intake
Less common than on the N47 • Medium- Symptoms
- Rough running, power loss, an intake flap fault code and, in the worst case, a broken flap arm being drawn into a cylinder.
- Cause
- The intake manifold's swirl flaps clog with soot from oil mist and EGR gases, which makes them stick. The problem remains on the B47 but is less common than on the N47 - we replace or professionally blank them off and clean the intake.
Clogged EGR & DPF on short trips
Common in city driving • High- Symptoms
- Power loss, frequent regeneration, limp mode and increased fuel consumption.
- Cause
- Insufficient regeneration cycles on very short trips and city driving make the EGR system and the particulate filter clog with soot faster than on motorway driving. We clean the intake and EGR in connection with cylinder head work.
Worn common-rail injectors
High mileage • Medium- Symptoms
- A knocking diesel noise, black or white smoke and hard starting, especially when cold.
- Cause
- The common-rail injectors wear over time and the copper washers that seal against the cylinder head lose their preload. We test, seal and replace injectors as needed.
BMW B47 rebuild pricing
Pricing based on B47 specifications: 4-cylinder inline, 84 mm bore, 16 valves, 5 main bearings + 4 rod bearings, aluminium block. We carry out cylinder boring, crankshaft grinding and cylinder head resurfacing with our own machine shop. The timing chain and turbo are handled separately. All prices exclude VAT and parts.
Cylinder head reconditioning
Bottom end
Full rebuild
Performance
The price covers machining work only. Parts and assembly/disassembly labour are charged separately.
Cylinder machining (4-cyl, 84 mm bore)
| Service | Price |
|---|---|
| Cylinder boring 4 cyl inline block (84 mm) | 3 318 kr |
| Plateau honing 4 cyl | 1 050 kr |
| Stress boring 4 cyl | 4 603 kr |
| O-ringing block 4 cyl (high-boost) | 2 800 kr |
| Deck decking block 4 cyl | 1 974 kr |
Crankshaft work (5 main + 4 big-end, 8 counterweights)
| Service | Price |
|---|---|
| Crankshaft grinding (5 main + 4 big-end) | 3 010 kr |
| Polishing standard | 1 022 kr |
| Cleaning 4-cyl crankshaft | 784 kr |
| Straightening (medium) | 1 190 kr |
| Camshaft journal grinding 4 pcs (DOHC) | 1 540 kr |
| Remove/fit counterweights 8 pcs | 2 044 kr |
Valve reconditioning (16 valves)
| Service | Price |
|---|---|
| Cutting 16 valve seats (standard) | 1 820 kr |
| Cutting 16 valve seats (large) | 2 772 kr |
| Valve guide replacement 16 pcs (light alloy) | 2 548 kr |
| Manufacture of valve seat inserts 16 pcs | 3 080 kr |
| Bronze sleeves fitting 16 pcs | 2 268 kr |
Resurfacing (I4, standard cylinder head size)
| Service | Price |
|---|---|
| Resurfacing cylinder head 4 cyl (standard) | 1 330 kr |
| Resurfacing cylinder head 4 cyl (large) | 1 596 kr |
| Resurfacing block 4 cyl (standard) | 1 988 kr |
| Resurfacing block 4 cyl (large) | 2 114 kr |
| Resurfacing manifold 4 cyl | 2 842 kr |
Con-rod work (4 pcs)
| Service | Price |
|---|---|
| Replace con-rod bush 4 pcs | 2 240 kr |
| Manufacture con-rod bush 4 pcs | 2 898 kr |
| Length adjustment con-rod 4 pcs | 2 898 kr |
| Replace press-fit piston 4 pcs | 1 582 kr |
| Replace piston ring 4 pcs | 1 106 kr |
| Resizing big-end housing 4 pcs | 2 352 kr |
| Check/straighten con-rod 4 pcs | 1 414 kr |
| Full reconditioning con-rod 4 pcs | 3 164 kr |
| Steel shot peening con-rods 4 pcs | 2 268 kr |
Pressure testing & balancing
| Service | Price |
|---|---|
| Pressure testing cylinder head 4 cyl (small) | 1 876 kr |
| Pressure testing cylinder head 4 cyl (large) | 2 800 kr |
| Pressure testing cylinder block | 1 400 kr /h |
| Balancing rotating assembly straight 4-cyl | 3 742 kr |
| Weight matching con-rods 4 pcs | 1 316 kr |
| Weight matching pistons 4 pcs | 1 092 kr |
| Flywheel balancing | 2 100 kr |
| Balancing flywheel + clutch | 2 842 kr |
Indicative pricing for the B47 configuration (4-cyl inline, 84 mm bore, 16 valves, alloy head, aluminium block). Labour prices exclude VAT and parts (piston rings, bearings, gaskets, stretch bolts, injectors, timing chain kit, EGR cooler, turbo). Request a quote for an exact price after inspection.
Tuning the BMW B47
The B47 is a rewarding diesel to build torque on, especially the twin-turbo variants. The aluminium block and the forged crankshaft take boost well on stock bearings - but the timing chain and the EGR cooler must be kept in order first.
- 1
Remapping & intake/exhaust
A Stage 1 remap, a freer intake and a downpipe give a big gain in torque thanks to the turbo capacity. The bottom end handles this well with the right margins and a healthy timing chain.
240-260 hk - 2
Upgraded injectors & Stage 2
Larger injectors and a Stage 2 remap take more out of the turbo system's margin. The stock bearings handle more boost with the right margins and a healthy turbo.
270-290 hk - 3
Turbo upgrade & reinforced fuel system
A hybrid turbo or an upgraded charge system together with a reinforced fuel system. Read more about turbo upgrades.
290-320 hk - 4
Full build
A balanced bottom end, ported cylinder head and a large charging system for anyone wanting to maximise a modern 2.0 diesel. We build the whole thing in-house with performance engine building.
320+ hk
Need a whole engine?
Sometimes the damage is too extensive for a rebuild to be worth it, or the car simply needs to be back on the road as fast as possible. That is when a ready-made replacement engine is the right way to go. Our replacement range includes reconditioned BMW B47-engines, quality assured to Meksta's standard and checked at our workshop in Tyresö before delivery, with a 12-month warranty and no mileage limit. Since the same engine code often covers several generations, we always verify against your chassis number before the build is ordered.
Questions & answers about the BMW B47
What we hear most often from B47 owners.
What does it cost to rebuild a BMW B47?
A cylinder head reconditioning costs around 5 000 - 7 000 kr (labour), a complete engine reconditioning around 19 500 - 30 500 kr. On top of that come parts (gasket, bearings, injectors, EGR cooler) and possibly a timing chain kit or turbo, depending on condition. We give a fixed quote after inspection.
Is the BMW B47 more reliable than the N47?
Yes. The B47 kept the N47's rear timing chain position, but with a reinforced chain, more robust guide rails, a redesigned tensioner and better oil supply. Chain failures are therefore far less common and come much later in the engine's life than on the N47. The shared EGR cooler recall with the N47 and N57 does, however, apply equally to all three engines.
Is the BMW B47 an interference engine?
Yes. If the timing chain jumps or breaks, the valves hit the pistons, which bends the valves and often causes major engine damage. A timing chain failure is uncommon on the B47, but a rattle from the rear of the engine should always be checked all the same.
Which cars have the BMW B47?
The B47 is found in virtually the whole of BMW's modern diesel range: the 1, 2, 3, 4 and 5 Series plus the X1, X2, X3, X4 and X5 in various power levels, and in the MINI Cooper SD (F54-F60).
Can you tune a B47?
Yes. A Stage 1 remap often gives a big increase in torque, especially on the twin-turbo variants. With upgraded injectors, Stage 2 and an optional turbo upgrade you build on from there. A healthy timing chain and a sorted EGR/DPF are a prerequisite before tuning.
See also: we recondition and build turbo engines and diesels from BMW and other manufacturers. Feel free to compare with the predecessor BMW N47 or BMW's inline six-cylinder diesel BMW N57. If you only need the turbo sorted, we do that via our turbo reconditioning. See all our engine types. Would you rather have a finished, reconditioned engine straight away? Buy a BMW B47 exchange engine in the shop.
Do you have a B47 that needs looking at?
Call us directly or send in a quote request. We reply within 24 hours.
Other engines we recondition
We recondition more engines than we have time to write guides about. Here are more that we see often.