1. Timing Chain and Tensioner Wear
Symptoms
Rattling from the front of the engine on cold startup, lasting several seconds until oil pressure builds. The rattle may also appear briefly when restarting a warm engine. In severe cases, a constant rattle or chain slap noise.
Cause
The M30 uses a single-row timing chain with a hydraulic tensioner and plastic guide rails. Over 200,000+ km, the chain stretches and the guides wear. The tensioner's hydraulic chamber drains when the engine sits, allowing slack in the chain on startup.
Fix
Replace the timing chain, tensioner, and guide rails.
The job is done from the front of the engine with the radiator removed.
Parts: Iwis chain ($80-100), tensioner ($120-180), guide rails ($80-120).
Labour: 4-6 hours.
Total workshop cost: $800-1,400.
Use only Iwis brand chains, cheap alternatives stretch prematurely.
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