MajorCommonEngine

Mitsubishi Triton: 4N15 2.4 valve clearances tightening up and burning valves with no warning noise

4N15 2.4 valve clearances tightening up and burning valves with no warning noise is a common engine fault on the Mitsubishi Triton on the 2015 onward cars, and we rate it major. Putting it right costs $600 to $5,000 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 34 documented faults on the Mitsubishi Triton.

Vehicle: Mitsubishi Triton
Engine: 2.4L
Years: 2015 onward
Fuel: diesel
System: Engine

This page covers the Mitsubishi Triton 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 Triton faults34 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph for this fault yet. We would rather show none than show a picture of something else.

What goes wrong

The 4N15 uses solid shim-under-bucket valve gear, and Mitsubishi requires the clearances to be measured and adjusted on a schedule - around every 45,000 km on earlier MQ cars and every 60,000 km on later ones. The inlet clearances close up as the valves bed into their seats, and the important part is that a tight valve makes no noise at all. It simply stops closing fully, loses the path that carries heat out of the valve into the head, and eventually burns. Because the engine sounds perfectly healthy, owners and some workshops skip the job, and the first real symptom is hard cold starting, a misfire or a flat spot - by which point the head is coming off. This is a service-history fault far more than a wear fault, so the invoices tell you much more than the car does.

What you would notice

Long or laboured cranking when cold, especially the first start of the day
Lumpy, uneven idle when cold that smooths out once warm
Flat spot or loss of power under load, sometimes with a check-engine light
No valve noise whatsoever - a tight valve is silent, unlike a loose one that ticks
Service book with no valve clearance check recorded at the scheduled intervals

How to check it

Where to look. Inside the cylinder head under the rocker cover, at the top of the engine. The only thing you can check yourself is the paperwork: the service book entries and the workshop invoices behind them.

This one is decided by the service book, so ask for it first and look for a valve clearance check and adjustment actually recorded at the scheduled interval, roughly every 45,000 km on earlier cars and every 60,000 km on later ones. Ask the seller directly whether the valve clearances have ever been measured and adjusted and by whom, because 'the dealer did all the services' is not the same answer - this item gets skipped, or ticked without being done, more often than anything else on the schedule. Start the engine from stone cold if you possibly can, and listen for drawn-out cranking and a rough first minute. Take it up a decent hill and feel whether it pulls cleanly to the top of each gear without a flat spot. Remember that a tight valve makes no sound at all, so a quiet engine is not evidence the job has been done. If a workshop inspection is possible: have a diesel specialist measure every clearance with a feeler gauge against Mitsubishi's figures and quote the shims before you agree a price.

What it costs to put right

$600 to $5,000 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

“Have the valve clearances ever been measured and adjusted, and at what kilometres?”
“Can I see the actual invoice for that service rather than just the stamp?”
“Does it ever crank for a long time when it is cold?”
“Who has serviced it - a Mitsubishi dealer, a diesel specialist, or a general workshop?”

Now check the Mitsubishi Triton 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 the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

Mitsubishi workshop manual procedure 'Valve clearance check and adjustment <4N15 (MIVEC)>'
newtriton.net thread 'MQ 4N15 valve clearance'
Pajero 4WD Club of Victoria forum thread 'MY17 valve clearance adjustment question'
4x4community.co.za thread '4N15 2.4 Mivec valve Clearance Adjustment'

Mitsubishi Triton buyer questions

Is 4n15 2.4 valve clearances tightening up and burning valves with no warning noise serious on a Mitsubishi Triton?

We rate it major and common on the Mitsubishi Triton. The 4N15 uses solid shim-under-bucket valve gear, and Mitsubishi requires the clearances to be measured and adjusted on a schedule - around every 45,000 km on earlier MQ cars and every 60,000 km on later ones. The inlet clearances close up as the valves bed into their seats, and the important part is that a tight valve makes no noise at all. It simply stops closing fully, loses the path that carries heat out of the valve into the head, and eventually burns. Because the engine sounds perfectly healthy, owners and some workshops skip the job, and the first real symptom is hard cold starting, a misfire or a flat spot - by which point the head is coming off. This is a service-history fault far more than a wear fault, so the invoices tell you much more than the car does.

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

$600 to $5,000 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 Triton years are affected?

Our research records this fault on the 2015 onward Mitsubishi Triton. 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.