Mitsubishi ASX: MIVEC Timing Chain Guide Rail Fracture (4B11)

The 4B11 2.0-litre MIVEC engine fitted to the ASX uses plastic composite timing chain guide rails and tensioner slipper pads to route and tension the camshaft drive chain. Over time heat cycling and oil degradation cause the plastic to become brittle and crack. Fractured guide fragments circulate in the oil and can cause chain rattle on cold start, erratic MIVEC variable valve timing phasing, and in severe cases allow the chain to skip a tooth causing significant timing drift and potential valve-to-piston contact. High-mileage examples often require a full timing chain kit replacement covering guides, tensioner, chain, and sprockets — a labour-intensive procedure requiring engine front cover removal.

• Rattling or slapping noise from front of engine on cold start lasting several seconds
• Rough or hunting idle when cold that settles after warm-up
• MIVEC variable valve timing fault codes P0011 or P0012
• Reduced power and worsening fuel economy
• Check engine light with camshaft position correlation codes

Cold-start the engine and listen carefully at the front of the engine bay for timing chain rattle lasting more than two seconds. Request an OBD scan for camshaft position and VVT codes. For any example over 130,000 km ask for evidence of timing chain replacement. Review oil service history as neglected intervals accelerate plastic guide degradation.

Parts involved: Timing chain.

≈A$1,470 to ≈A$3,500 at independent workshop rates, shown as an approximate guide in Australian dollars. That is for this job on its own, not for the car.

An estimate, converted to Australian dollars, 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 and plastic guide rails ever been replaced, and is there a receipt?”
• “Does the engine make any rattle or slapping noise when started from cold?”
• “Are there any stored or active fault codes related to valve timing or camshaft position?”
• “What oil specification and change interval has been used throughout ownership?”

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.