Holden Commodore: V6 Timing Chain Tensioner Rattle at Startup

The LY7 3.6L V6 in VE and the LFX/LE0 variants in VF use a dual overhead cam layout with timing chains on both cylinder heads driven from the block. The primary chain tensioner and secondary tensioner arms are hydraulically loaded by engine oil pressure. At cold start, oil drains from the tensioner galleries overnight, leaving the chains slack for 2–5 seconds until pressure builds. Over time the tensioner check valves and ratchet pawls wear, increasing bleed-down. By 120,000–160,000km the tensioners lose their ability to maintain pre-load, causing chains to whip against guides. Prolonged neglect allows the chain to jump a tooth on the cam sprocket, causing catastrophic valve-to-piston contact. GM issued multiple calibration updates and revised tensioner part numbers for this engine family across the VE/VF production run.

• Loud rattling or chattering noise from the front of the engine for 2–5 seconds at cold start, then clearing
• Rattle present at hot restart after engine has sat for 30+ minutes
• Check Engine Light with cam position or cam-crank correlation codes (P0016, P0017, P0341, P0346)
• Rough running or misfires if chain has jumped a tooth on the camshaft sprocket
• Timing chain noise audible above idle if tensioner is severely worn

1. 1

   Cold-start the engine and listen at the front right of the engine bay for chain rattle before oil pressure builds.

2. 2

   Let the engine reach operating temperature, shut it off for 20 minutes, then restart and listen again.

3. 3

   Scan for cam correlation or VVT codes.

4. 4

   Check oil level and condition — dirty or low oil accelerates tensioner wear.

5. 5

   Ask when timing chains were last inspected and whether updated tensioner part numbers have been fitted.

Parts involved: Timing chain.

$1,600 to $3,800 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 rattle ever been investigated or the tensioners replaced?”
• “What oil change interval was followed and what viscosity was used?”
• “Have any cam position or timing correlation fault codes appeared?”
• “Has the engine ever been noted as 'noisy on cold start' in service records?”

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.