Toyota Mark II: Timing Belt Tensioner Pulley Bearing Collapse

The 1JZ-GTE and 2JZ-GE engines fitted to JZX100 and JZX110 Mark II models use a rubber timing belt driven by a spring-loaded hydraulic tensioner and a fixed idler pulley. The tensioner pulley bearing and idler pulley bearing are known to fatigue and collapse — particularly on vehicles where the original belt has not been replaced at the Toyota-specified 100,000 km interval. Bearing collapse causes the belt to skip teeth or jump off entirely, resulting in catastrophic piston-to-valve contact on the interference-design engine. Imported JZX100 examples often arrive in Australia at 100,000–180,000 km with no evidence of belt service history.

• Rattling or chirping noise from front of engine at startup
• Squealing belt noise under load
• Engine suddenly stalls and will not restart
• Complete engine destruction if belt jumps on interference engine
• Timing belt warning light (where fitted) or service interval overdue

Spin the tensioner and idler pulleys by hand — any roughness, grinding, or play indicates bearing wear. Check for workshop records proving belt, tensioner, and idler were replaced together. Verify water pump was done simultaneously as it shares the belt circuit. If a workshop inspection is possible: Remove the upper timing cover to physically inspect the belt for cracking, fraying, or glazing.

Parts involved: Timing belt.

≈A$830 to ≈A$2,210 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.

• “When was the timing belt last replaced and by which workshop?”
• “Was the tensioner pulley, idler pulley, and water pump replaced at the same time?”
• “Is there a receipted service history showing timing belt work?”
• “What is the current odometer reading versus the last belt service mileage?”

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.