BMW N57 Rebuild, common faults & everything you need to know
A complete guide to BMW's inline 3.0 diesel - a common-rail inline-six with DOHC 24v in single-turbo, sequential twin-turbo or triple-turbo form (N57S in the M550d and X5/X6 M50d). From the rear 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 N57 is BMW's inline 3.0 diesel that replaced the M57 and is found in everything from the 3 Series to the 7 Series, X3, X4, X5 and X6. It is a common-rail inline-six with DOHC, 24 valves and an aluminium block with cast-iron liners, in three forced-induction forms: single-turbo, sequential twin-turbo and the rare triple-turbo N57S in the halo models M550d, 750d and X5/X6 M50d. The bottom end, with its forged crankshaft, is robust, and the rear timing chain is considerably more reliable than on the N47 - but it sits in the same exposed position and requires the same separation of engine and gearbox to replace. The shared EGR cooler recall with the N47 and B47 (coolant leaking into the intake) applies to all three engine families. 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 N57 at a glance
Shared base data for the N57D30 family. Variant-specific power and torque figures are listed in the table below, compiled from BMW's variant lists and cross-verified spec databases (at least two independent sources per value).
| Variant (code) | Forced induction | Power | Torque | Year |
|---|---|---|---|---|
| N57D30O0 | Single-turbo | 245 hk | 520-540 Nm | 2008-2014 |
| N57D30O1 | Single-turbo | 258 hk | 560 Nm | 2011-2019 |
| N57D30T0 Twin-turbo | Sequential twin-turbo | 306 hk | 600 Nm | 2009-2017 |
| N57D30T1 Twin-turbo | Sequential twin-turbo | 313 hk | 630 Nm | 2011-2018 |
| N57S (N57D30S1) Triple-turbo | Triple-turbo (2 small + 1 large) | 381 hk | 740 Nm | 2012-2018 |
The power and torque figures above are identity data (the engine's output per code, not tightening torques), cross-verified against Wikipedia and independent spec databases (mymotorlist, torquecars). The sources give the N57D30O0 as a range (520-540 Nm) depending on model year/update. The N57S is the triple-turbo variant in the M550d, 750d/750Ld and the X5 and X6 M50d.
Torque specs
We only publish torque specs we have been able to verify against an actual factory page. For the N57 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 a job of your own, get in touch and we will look them up in the correct factory manual before your job starts.
Common problems on the BMW N57
This is what we see most often when an N57 comes in. Symptoms, causes and how we fix them.
EGR cooler - coolant into the intake
Shared recall with the N47/B47 • 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 is serious and widespread enough that it has been the basis for an international recall covering the N47, N57 and B47 together. We check and replace the EGR cooler as part of larger engine work.
Rear timing chain & guide rails
Less common than on the N47 • High- Symptoms
- A rattling noise from the rear of the engine on cold start, fault codes for camshaft versus crankshaft position. Because the N57 is an interference engine, the result is bent valves if the chain jumps or breaks.
- Cause
- Like the N47, the N57 has its timing chain mounted at the rear against the flywheel and gearbox side, but with a single-row chain, reinforced guide rails and a sturdier tensioner that make failures far less common and later in the engine's life. Because the chain sits at the back, separating the engine and gearbox is still required to reach it.
Broken swirl flaps in the intake
Common • High- Symptoms
- Rough running, power loss, a fault code for the intake flap and, in the worst case, a broken flap arm or bush being drawn into a cylinder.
- Cause
- The intake manifold's swirl flaps and their linkage clog with soot from oil mist off the crankcase ventilation and EGR exhaust gas, which makes them stick and eventually break off. We replace or professionally blank them off and clean the intake.
Worn common-rail injectors
High mileage • Medium- Symptoms
- A knocking diesel noise, black or white smoke, hard starting and soot deposits around the injectors' copper washers in the cylinder head.
- Cause
- The Bosch common-rail injectors wear and the copper washers that seal against the cylinder head lose their preload, which leaks exhaust gas past the injector. Left untreated, the soot can eventually seize the injector in the cylinder head. We test, seal and replace injectors as needed.
Turbo actuator & variable vanes
High mileage, multi-turbo variants most sensitive • High- Symptoms
- Lost boost, limp mode, a whistle under load and a fault code for underboost or overboost. On the twin- and triple-turbo variants the transition between the turbos can become uneven.
- Cause
- The variable vanes seize with soot and the electric actuator wears over time. The more turbochargers, the more actuators and linkages that can play up - the triple-turbo's changeover between the small turbos and the large one is particularly calibration-sensitive. We recondition or replace the turbo as part of the overhaul.
BMW N57 rebuild pricing
Pricing based on N57 specifications: 6-cylinder inline, 84 mm bore, 24 valves, 7 main bearings + 6 rod bearings, aluminium block with cast-iron liners. We carry out cylinder boring, crankshaft grinding and cylinder head resurfacing with our own machine shop. The rear 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 (6 cyl, 84 mm bore)
| Service | Price |
|---|---|
| Cylinder boring 6 cyl inline block (84 mm) | 4 977 kr |
| Plateau honing 6 cyl | 1 450 kr |
| Stress boring 6 cyl | 5 980 kr |
| O-ringing block 6 cyl (high-boost) | 3 600 kr |
| Deck resurfacing block 6 cyl | 2 700 kr |
Crankshaft work (7 mains + 6 big-ends, 12 counterweights)
| Service | Price |
|---|---|
| Crankshaft grinding (7 mains + 6 rods) | 5 000 kr |
| Polishing standard | 1 022 kr |
| Cleaning 6-cyl crankshaft | 920 kr |
| Straightening (large) | 1 400 kr |
| Camshaft journal grinding 14 (DOHC) | 4 312 kr |
| Remove/refit counterweights 12 | 3 066 kr |
Valve reconditioning (24 valves)
| Service | Price |
|---|---|
| Cutting 24 valve seats (standard) | 2 730 kr |
| Cutting 24 valve seats (large) | 4 158 kr |
| Valve guide replacement 24 (light alloy) | 3 822 kr |
| Manufacturing valve seat rings 24 | 4 620 kr |
| Bronze sleeves fitting 24 | 3 402 kr |
Resurfacing diesel (I6, large cylinder head size)
| Service | Price |
|---|---|
| Cylinder head resurfacing 6 cyl (standard) | 1 800 kr |
| Cylinder head resurfacing 6 cyl (large) | 2 100 kr |
| Block resurfacing 6 cyl (standard) | 2 400 kr |
| Block resurfacing 6 cyl (large) | 2 700 kr |
| Resurfacing manifold 6 cyl | 3 800 kr |
Connecting rod work (6)
| Service | Price |
|---|---|
| Small-end bushing replacement 6 (Ø22 mm piston pin) | 3 360 kr |
| Manufacturing small-end bushings 6 | 4 347 kr |
| Length adjustment connecting rod 6 | 4 347 kr |
| Press-fit piston replacement 6 | 2 373 kr |
| Piston ring replacement 6 | 1 659 kr |
| Big-end resizing 6 | 3 528 kr |
| Inspection/straightening connecting rod 6 | 2 121 kr |
| Full reconditioning connecting rod 6 | 4 746 kr |
| Shot peening connecting rods 6 | 3 402 kr |
Pressure testing & balancing
| Service | Price |
|---|---|
| Cylinder head pressure testing 6 cyl (small) | 2 814 kr |
| Cylinder head pressure testing 6 cyl (large) | 4 200 kr |
| Pressure testing cylinder block | 1 400 kr /h |
| Rotating assembly balancing inline 6 cyl | 5 100 kr |
| Weight matching connecting rods 6 | 1 974 kr |
| Weight matching pistons 6 | 1 638 kr |
| Flywheel balancing | 2 100 kr |
| Balancing flywheel + clutch | 2 842 kr |
Indicative pricing for the N57 configuration (6-cylinder inline, 84 mm bore, 24 valves, alloy head, aluminium block with cast-iron liners). 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 N57
The N57 is a rewarding diesel to build torque on, especially the twin- and triple-turbo variants. The aluminium block and the forged crankshaft take boost well on stock bearings, but the rear timing chain and 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 increase in torque thanks to the already generous turbo capacity. The bottom end handles this well with a healthy rear timing chain and a clean intake.
350-380 hk - 2
Upgraded injectors & Stage 2
Larger injectors and a Stage 2 remap take more out of the turbo system's margin, especially on the twin-turbo variants. The stock bearings handle more with the right margins and a healthy turbo.
400-430 hk - 3
Turbo upgrade
A hybrid turbo or an upgraded charging system together with a reinforced fuel system. Opens the power window further for a 3.0 diesel. Read more about turbo upgrades.
430-450 hk - 4
Full build
A balanced bottom end, a ported cylinder head and a large charging system for those who want to maximise an already powerful inline-six. We build the whole thing in-house with performance engine building.
450+ 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 N57-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 N57
What we hear most often from N57 owners.
What does it cost to rebuild a BMW N57?
A cylinder head reconditioning costs around 7 500 - 10 500 kr (labour), a complete engine reconditioning around 28 500 - 43 500 kr. On top of that come parts (gasket, bearings, injectors, EGR cooler) and possibly a rear timing chain kit or turbo, depending on condition and variant. We give a fixed quote after inspection.
Is the BMW N57 more reliable than the N47?
Yes, on the rear timing chain specifically. The N57 has a single-row timing chain in the same rear position as the N47, but with reinforced guide rails and a sturdier tensioner, which makes failures far less common and later in the engine's life. Chain problems still occur, though more rarely. The shared EGR cooler recall with the N47 and B47 applies to all three engine families equally.
How does the triple-turbo in the N57S (M550d, X5 M50d) work?
The N57S has three turbochargers: two small turbos work sequentially at low revs to eliminate turbo lag, and a third, larger turbo takes over at higher revs and load for peak power. The transition between the small turbos' and the large turbo's operating range is calibration-sensitive and requires the right diagnostics for boost problems.
Is the BMW N57 an interference engine?
Yes. If the rear timing chain jumps or breaks, the valves hit the pistons, which bends the valves and often causes major engine damage. A rattle from the rear of the engine on cold start should always be investigated.
Which cars have the BMW N57?
The N57 is found in the BMW 3 Series (330d/335d), 5 Series (530d/535d), 7 Series (730d/740d), 4 Series (430d/435d) and the X3, X4, X5 and X6 in various 30d-40d forms. The rare triple-turbo variant N57S is found in the M550d, 750d/750Ld and the X5 and X6 M50d.
Can you tune an N57?
Yes. A Stage 1 remap often gives a big torque increase on the twin-turbo variants thanks to the already generous factory turbo capacity. With upgraded injectors, Stage 2 and a possible turbo upgrade you build on from there. A healthy rear timing chain and a sorted EGR cooler 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 BMW's four-cylinder diesel BMW N47 or Mercedes' own six-cylinder diesel Mercedes OM606. 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 N57 exchange engine in the shop.
Do you have an N57 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.