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BMW X3: B47 Timing Chain Tensioner Cold-Start Rattle

B47 Timing Chain Tensioner Cold-Start Rattle is a common engine fault on the BMW X3 on the 2017 onward cars, and we rate it major. Putting it right costs $1,800 to $5,500 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 42 documented faults on the BMW X3.

Vehicle
BMW X3
Engine
B47
Years
2017 onward
Fuel
diesel
System
Engine

This page covers the BMW X3 as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All BMW X3 faults42 documented faults on this model

What you are looking at

The front of a dual overhead camshaft engine with the timing cover removed, exposing the timing chain and sprockets.Example of the part — not this vehicle

The front of a twin-cam engine with the timing cover off — chain, sprockets and guides.

Logansenf · CC BY-SA 4.0 · Wikimedia Commons

What goes wrong

The B47D20 engine retains the rear-mounted timing chain layout inherited from the N47 and early production G01 units exhibit hydraulic tensioner wear that causes audible chain rattle for several seconds on cold starts before oil pressure is fully established. Although less immediately catastrophic than the N47 pattern, sustained operation with a degraded tensioner accelerates chain stretch and guide rail wear, ultimately leading to the same expensive repair path. BMW released a revised tensioner assembly under an updated part number for in-warranty replacement.

What you would notice

  • Audible chain rattle from rear of engine lasting 3 to 10 seconds on first cold start of the day
  • Rattle disappears once oil pressure is established at idle
  • Intermittent VANOS or camshaft-correlation fault codes stored in DME
  • Slight hesitation or timing irregularity under light load when cold

How to check it

Where to look. Rear timing chain case on B47 engine, accessible from the firewall side of engine bay

  1. Perform a cold start having confirmed the engine has not run for at least four hours.

  2. Listen from the firewall side of the engine bay for chain rattle.

  3. Scan DME for stored VANOS or camshaft-position fault codes including codes that may have self-cleared.

  4. Ask for evidence that the tensioner was replaced with the revised BMW part number.

Parts involved: Timing chain.

What it costs to put right

$1,800 to $5,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

  • “Has the timing chain tensioner been inspected or replaced with the revised BMW part?”
  • “Does the engine make any rattling sound on the first start of the day?”
  • “Have any VANOS or timing-related fault codes ever been stored or flagged?”

Now check the BMW X3 you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

BMW X3 buyer questions

Is b47 timing chain tensioner cold-start rattle serious on a BMW X3?

We rate it major and common on the BMW X3. The B47D20 engine retains the rear-mounted timing chain layout inherited from the N47 and early production G01 units exhibit hydraulic tensioner wear that causes audible chain rattle for several seconds on cold starts before oil pressure is fully established. Although less immediately catastrophic than the N47 pattern, sustained operation with a degraded tensioner accelerates chain stretch and guide rail wear, ultimately leading to the same expensive repair path. BMW released a revised tensioner assembly under an updated part number for in-warranty replacement.

How much does it cost to fix on a BMW X3?

$1,800 to $5,500 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which BMW X3 years are affected?

Our research records this fault on the 2017 onward BMW X3. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Perform a cold start having confirmed the engine has not run for at least four hours. Listen from the firewall side of the engine bay for chain rattle. Scan DME for stored VANOS or camshaft-position fault codes including codes that may have self-cleared. Ask for evidence that the tensioner was replaced with the revised BMW part number. Look here: Rear timing chain case on B47 engine, accessible from the firewall side of engine bay