CriticalCommonEngine

Mitsubishi Legnum: Timing Belt Failure — Interference Engine (6A12 V6 / 4G93T)

Timing Belt Failure — Interference Engine (6A12 V6 / 4G93T) is a common engine fault on the Mitsubishi Legnum on the 1996–2002 cars, and we rate it critical. Putting it right costs $600 to $6,500 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
Engine: 6A12 / 4G93-T
Years: 1996–2002
Fuel: petrol
Gearbox: auto
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

Both the 6A12 V6 and 4G93T engines fitted to the Legnum EC5W are interference designs; belt failure causes immediate piston-to-valve contact resulting in bent valves and cylinder head damage. Japanese-market imports frequently arrive with unknown or unverifiable service history. The 4G93T turbo variant runs higher thermal and belt loads, further shortening belt life from heat cycling. The service interval is 90,000 km or 5 years, whichever comes first.

What you would notice

Engine stops suddenly with no restart
Loud mechanical bang at moment of belt failure
Engine cranks freely but will not start post-failure
No compression on multiple cylinders after failure
Rattling from timing cover area on worn tensioner bearing

How to check it

Where to look. Front of engine block behind plastic timing cover, passenger side

Demand a dated timing belt replacement record — a sticker on the radiator shroud or stamp in the service book. If no records exist, budget for immediate belt, tensioner, and water pump replacement before driving. Inspect the timing cover for oil contamination that can degrade the belt prematurely.

Parts involved: Timing belt.

What it costs to put right

$600 to $6,500 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.

Ask the seller

“Has the timing belt been replaced and do you have written records?”
“Were the water pump and tensioner replaced at the same time?”
“What is the odometer reading since the last belt change?”

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 timing belt failure — interference engine (6a12 v6 / 4g93t) serious on a Mitsubishi Legnum?

We rate it critical and common on the Mitsubishi Legnum. Both the 6A12 V6 and 4G93T engines fitted to the Legnum EC5W are interference designs; belt failure causes immediate piston-to-valve contact resulting in bent valves and cylinder head damage. Japanese-market imports frequently arrive with unknown or unverifiable service history. The 4G93T turbo variant runs higher thermal and belt loads, further shortening belt life from heat cycling. The service interval is 90,000 km or 5 years, whichever comes first.

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

$600 to $6,500 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 1996–2002 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.