Toyota Mark II: 1JZ-GE Timing Belt Failure on Neglected Examples

The 1JZ-GE 2.5-litre inline-six uses a rubber timing belt that Toyota specifies for replacement at 100,000 km intervals. On JZX90 examples imported into New Zealand with incomplete service histories, the belt is routinely found well beyond this interval. The engine is an interference design, meaning belt failure causes piston-to-valve contact and catastrophic internal damage. Oil contamination from a weeping valve cover gasket accelerates belt degradation significantly.

• Engine cranks but will not start — indicating belt has already jumped teeth or snapped
• Ticking or light rattling from the timing cover area at idle, worsening when cold
• Oily residue visible on the outer surface of the timing belt when cover is partially removed
• Rough idle or misfires caused by ignition timing being thrown off by a stretched or skipped belt

1. 1

   Check belt tension with light finger pressure; a correctly tensioned belt should not deflect more than 10–15 mm. Inspect the valve cover gasket area above the belt run for oil weeping.

2. 2

   Ask for written proof of replacement with mileage and date.

3. 3

   If a workshop inspection is possible: Remove the timing cover inspection plug or lower cover section to visually assess belt condition — look for cracking, glazing, fraying at edges, or oil contamination.

Parts involved: Timing belt.

$450 to $5,500 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.

• “Can you show me documentation of when the timing belt was last replaced and at what mileage?”
• “Has the water pump and idler pulley been replaced at the same time as the timing belt?”
• “Has any oil leak from the valve cover or cam seals been repaired before it could contaminate the belt?”

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.