BMW 1 Series: B47 2.0D Timing Chain Tensioner Wear & Cold Rattle

The B47 diesel engine was intended to improve on the N47 but retains a hydraulic timing chain tensioner that loses pressure when oil is cold and thick. This causes a characteristic metallic rattle immediately on startup that subsides within 5 to 30 seconds once oil pressure builds. Prolonged neglect leads to guide rail wear and measurable chain stretch. If left unaddressed the tensioner can fail to maintain adequate chain tension at operating temperature, escalating to a critical failure similar to the N47. Correct oil specification and short warm-up procedure are essential.

• Metallic rattling noise from top of engine on cold start lasting 5 to 30 seconds
• Rattle disappears once engine reaches normal operating temperature
• Occasional check engine light with camshaft or timing-related fault codes
• Rough or lumpy idle during initial cold start period
• Increased noise when restarting a fully warm engine after a brief stop

1. 1

   Cold-start the engine from fully cold and listen immediately for chain rattle from the timing cover area.

2. 2

   Check service records for oil change regularity using the correct BMW Longlife-04 or LL-17FE+ specification.

3. 3

   Ask whether any BMW technical service bulletin regarding B47 tensioner has been carried out.

4. 4

   Scan for stored timing or camshaft position fault codes.

Parts involved: Timing chain.

$3,500 to $9,000 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.

• “Has the timing chain tensioner been replaced or inspected?”
• “Does the engine make any rattling noise on a cold start?”
• “What oil specification and brand has been used at each service?”
• “Has any BMW technical service bulletin regarding the B47 timing system been completed?”

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.