The N47 engine powers a large proportion of BMW's diesel range — 116d, 118d, 120d, 318d, 320d — and it is associated with one of the most well-documented design flaws in the Bavarian marque's recent history: premature timing chain failure on the crankshaft side. This problem is not caused by poor maintenance — it is structural, inherent to the engine's very architecture, and can occur from as little as 100,000 km. EDEN BOITES explains the mechanics behind this fault, the warning signs you should never ignore, and the most reliable solution to get your vehicle back on the road without a lengthy lay-up.
Our available references for this model
Why does the N47 timing chain fail so often?
What makes the N47 unusual is the position of its timing chain: unlike the vast majority of engines, which place the timing components on the accessory side (at the front of the block), BMW chose to position the N47's chain on the flywheel side — at the rear of the block. This decision has serious consequences:
- The chain is difficult to access for inspection and preventive maintenance.
- It is the last component to receive oil during a cold start, increasing wear every time the engine is started.
- The original chain tensioner has a fragile design that gradually loses tension, causing slack and rattling.
- The plastic chain guide breaks up under the effects of heat and repeated engine cycles, leaving debris in the sump.
The result: a chain that stretches, jumps, and ultimately snaps — sometimes without warning — causing, in the most severe cases, piston-to-valve contact and complete engine destruction.
What are the symptoms of a failing timing chain on the N47?
Recognising the warning signs can make all the difference between a preventive chain replacement and a completely written-off engine:
- Cold metallic rattle: a dull or metallic noise on start-up that fades after a few seconds is often the first sign. It indicates that the chain lacks tension before oil pressure builds up.
- Persistent rattling noise: if the rattle no longer disappears once the engine is warm, the chain is already heavily worn.
- Engine warning light and camshaft timing warning illuminated simultaneously: camshaft timing faults generate error codes related to the valve timing system.
- Rough or uneven idle: the engine stumbles, misfires, and loses smoothness.
- Sudden loss of power: if the chain jumps, power drops sharply and the engine may cut out spontaneously.
- Metal swarf in the engine oil: during an oil change, the presence of metallic particles indicates advanced deterioration of the guide or tensioner.
Warning: on the N47, failure can occur with very little prior warning. A vehicle running normally can break down without notice if the chain snaps suddenly. Never dismiss a cold rattle on this engine.
Which N47 references are available as reconditioned engines at EDEN BOITES?
EDEN BOITES offers two reconditioned versions of the N47 2.0d engine, suitable for BMW 1 Series and 3 Series vehicles fitted with this block:
| Reference | Engine | Engine code | Part type | Sale type |
|---|---|---|---|---|
| N47D20C | 2.0d | N47D20C | Bare engine | Exchange |
| N47D20D | 2.0d | N47D20D | Bare engine | Exchange |
These engines are sold as bare units. The exact engine code is stamped on the block, typically on the sump casing. Please have this code and your vehicle's VIN to hand when requesting a quote.
Browse our full range of available BMW engines in our BMW collection.
Exchange: how does it work in practice?
The N47D20C and N47D20D engines are sold on an exchange basis. This means you receive a reconditioned engine and then return your old block as a core unit — this return is mandatory. This process maintains a consistently high quality standard by using a stock of recovered cores that are inspected and rebuilt to rigorous specifications. The customer receives an engine whose internal tolerances have been restored to original factory dimensions, with the timing chain correctly positioned and all wear components replaced.
Reconditioned engine vs second-hand engine: why is a used N47 particularly risky?
With this specific engine, buying a second-hand block is a very risky gamble. Here is why:
- There is no way to assess the condition of the rear timing chain without partially dismantling the engine.
- A used N47 with 80,000 km on the clock may already have a chain at the end of its life if cold starts have been frequent or oil changes have been overdue.
- If the tensioner or guide is already failing, the problem will reappear quickly after fitting.
- There is no meaningful warranty on a second-hand engine pulled from a breaker's yard.
A reconditioned engine from EDEN BOITES is covered for up to 24 months on the part, offering incomparable peace of mind compared with a second-hand engine sold as seen. The saving compared with a new unit from the manufacturer can amount to several thousand pounds, whilst still benefiting from a part restored to original tolerances.
What other reconditioned BMW 1 Series engines does EDEN BOITES offer?
Beyond the N47 diesel, EDEN BOITES covers an extended range for the BMW 1 Series, including:
- B37D15A — 1.5d 1 Series (exchange, bare engine)
- N13B16A — 1.6i 1 Series (exchange, up to 24-month parts warranty)
- N45B16A — 1.6i 1 Series (rebuild of your own unit)
- N20B20A, N20B20B, N20B20D — 2.0i 1 Series (exchange)
Every engine is sold as a bare unit. Ancillary components (timing kit, turbo, injection system, alternator, etc.) are not included; a precise list is provided with your quote depending on your configuration.
FAQ — BMW N47 Engine: timing chain, failure and rebuild
Does a cold rattle on my BMW diesel always mean the N47 timing chain?
Not necessarily, but on an N47 (116d, 118d, 120d, 318d, 320d), a cold rattle that fades after a few seconds is the characteristic sign of a worn chain tensioner or a chain guide that is beginning to deteriorate. This symptom must be taken seriously straight away: a proper diagnosis by a professional is essential before the chain jumps or snaps.
At what mileage does the N47 timing chain typically fail?
Failures have been recorded between 80,000 and 180,000 km, with no consistent pattern. The frequency of cold starts, the quality of oil used, and adherence to oil change intervals all directly affect service life. Failures below 100,000 km are well documented, which confirms that the problem is structural in nature rather than simply the result of normal wear.
Can the timing chain be replaced without changing the entire engine?
If the chain has jumped but has not caused piston-to-valve contact, replacing the chain, tensioner and guides may be sufficient. However, if the engine has suffered internal mechanical damage (bent valves, damaged pistons), a complete rebuild of the block is necessary. A reconditioned N47D20C or N47D20D engine is then the most reliable and most cost-effective solution compared with a new unit from the manufacturer.
What is an exchange and do I have to send my old engine back?
Yes, the exchange process requires you to return your old engine block after receiving the reconditioned unit. This return is mandatory. Your old unit will be inspected, reconditioned and reintroduced into the production cycle. This process guarantees the consistent quality of the reconditioned engines offered by EDEN BOITES and keeps prices well below those of a new manufacturer unit.
What warranty is provided on a reconditioned N47 engine from EDEN BOITES?
The N47D20C and N47D20D references carry a warranty of up to 24 months on the part. This warranty covers the part itself. Full terms and conditions are provided at the time of ordering.
How do I identify my N47 engine code to order the correct reference?
The engine code is stamped directly on the block, usually on the casing near the cylinder head or on a data plate. It begins with N47 followed by the variant (D20C, D20D, etc.). This code, combined with your VIN (the vehicle's 17-character serial number), allows the exact reference to be identified without ambiguity. If in doubt, send these details via our online quote form.
Is it possible to pay for the reconditioned engine in instalments?
Yes, EDEN BOITES offers the option to pay in up to 10 instalments. Details of the instalment payment options are provided when finalising your order or on request at the time of your quote.
What is the delivery lead time for a reconditioned N47 engine?
Lead times are confirmed at the quote stage, depending on the reference, your location and availability at the time of ordering. Please enquire via the online quote form for a precise estimate.
🔍 Request your BMW N47 engine quote
Please provide the following details to receive a fast and accurate response:
- Your vehicle model (e.g. BMW 118d, 320d, etc.)
- Engine and engine code (e.g. N47D20C)
- VIN or chassis number (17 characters)
- Gearbox number if applicable
