Crankshaft pulley bolt letting go

The Montero specialist who supplies the updated fastener describes the original crankshaft centre bolt as a defective design that would often back out and break, ruining the crankshaft and sometimes other engine components with it, and sells the replacement with thread locker already applied. Mitsubishi ran a factory campaign for the same fastener on the previous generation's smaller V6 and on another model. That campaign is not this engine and this entry does not claim it is — but it is worth reading, because the manufacturer's own stated consequence is a loss of power steering assist and an increased risk of a crash, and the manufacturer's own remedy was to tighten the bolt to the correct torque specification, replacing it only where it was damaged. This entry is scoped to the bolt already going: every symptom below — a pulley you can see wobbling, a knock from the nose of the crankshaft, a thrown accessory belt — is the failure in progress, which is why the triage is do not drive. A truck that simply still has the original bolt in it, with none of those signs, is a different situation: that is the factory campaign's own remedy, a torque check at the next service, not a reason to park it. **A warning about the popular shortcut.** Enthusiasts pass around a way to tell the two bolts apart by eye, from how far the head stands out of the pulley. The suppliers who sell the part do not describe it the same way round as each other, and this site could not reach a source good enough to settle which direction is correct — so it is not printed here. Identify the bolt by its part number instead. Getting that test backwards would tell an owner the defective bolt is the good one.

Gen 32001–2006Damages other partsCommunity consensusSafety-critical