CriticalCommonEngine

Mitsubishi Legnum: 6A13TT Timing Belt Tensioner & Idler Bearing Failure

6A13TT Timing Belt Tensioner & Idler Bearing Failure is a common engine fault on the Mitsubishi Legnum on the 1996–2003 cars, and we rate it critical. Putting it right costs $750 to $1,600 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 6 documented faults on the Mitsubishi Legnum.

Vehicle: Mitsubishi Legnum
Only on: Bi-Turbo / twin-turbo
Engine: 6A13-TT
Years: 1996–2003
Fuel: petrol
System: Engine

This page covers the Mitsubishi Legnum as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Mitsubishi Legnum faults6 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph of the Timing belt yet. We would rather show none than show a picture of a different part.

What goes wrong

The Legnum EC with 6A13 2.5L twin-turbo DOHC V6 is a fully interference-configuration engine where timing belt failure causes immediate and total engine destruction through piston-to-valve contact. The hydraulic auto-tensioner loses its internal damping as seals age, while the idler bearings are subject to accelerated degradation in the turbocharged thermal environment — turbo heat soak raises ambient underbonnet temperatures well beyond naturally aspirated equivalents, breaking down bearing grease faster. The dual overhead cam arrangement also places greater rotational load on the belt than a single-cam engine. Many NZ-imported Legnums arrive with incomplete Japanese service records, and the labour-intensive cover removal process means this critical service is frequently deferred or skipped.

What you would notice

High-pitched chirping or ticking at idle from timing belt cover area
Belt slap or rattling noise on cold start settling after warm-up
Engine misfires or rough running if belt has jumped teeth
Complete engine stall and refusal to restart on full belt breakage

How to check it

Where to look. Front centre of engine block behind plastic timing belt covers; partially accessible from the driver-side front wheel arch

Manually spin each idler pulley checking for bearing roughness, noise or wobble. Verify tensioner rod extension position indicates live hydraulic pressure. Confirm water pump impeller integrity and check for weep-hole seepage while covers are removed. If a workshop inspection is possible: Remove both upper and lower timing belt covers and inspect the belt surface for cracking, glazing, fraying or oil contamination.

Parts involved: Timing belt.

What it costs to put right

$750 to $1,600 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.

Ask the seller

“Can you provide receipts confirming the last timing belt service?”
“Were all idler pulleys and the tensioner hydraulic unit replaced at that service?”
“Has the car had any misfires, rough running or unexpected stalling?”

Now check the Mitsubishi Legnum you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

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.

Mitsubishi Legnum buyer questions

Is 6a13tt timing belt tensioner & idler bearing failure serious on a Mitsubishi Legnum?

We rate it critical and common on the Mitsubishi Legnum. The Legnum EC with 6A13 2.5L twin-turbo DOHC V6 is a fully interference-configuration engine where timing belt failure causes immediate and total engine destruction through piston-to-valve contact. The hydraulic auto-tensioner loses its internal damping as seals age, while the idler bearings are subject to accelerated degradation in the turbocharged thermal environment — turbo heat soak raises ambient underbonnet temperatures well beyond naturally aspirated equivalents, breaking down bearing grease faster. The dual overhead cam arrangement also places greater rotational load on the belt than a single-cam engine. Many NZ-imported Legnums arrive with incomplete Japanese service records, and the labour-intensive cover removal process means this critical service is frequently deferred or skipped.

How much does it cost to fix on a Mitsubishi Legnum?

$750 to $1,600 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Mitsubishi Legnum years are affected?

Our research records this fault on the 1996–2003 Mitsubishi Legnum. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.