MajorCommonCooling

Mitsubishi Delica: 6G72 V6 overheating under load from thermostat/water pump/radiator

6G72 V6 overheating under load from thermostat/water pump/radiator is a common cooling fault on the Mitsubishi Delica on the 2000–2006 cars, and we rate it major. Putting it right costs $400 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 18 documented faults on the Mitsubishi Delica.

Vehicle: Mitsubishi Delica
Engine: 6G72
Years: 2000–2006
Fuel: petrol
System: Cooling

This page covers the Mitsubishi Delica 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 Delica faults18 documented faults on this model

What you are looking at

An annotated photograph of an automotive engine thermostat identifying the wax capsule and both disc valves. — A double-valve engine thermostat, labelled: the wax capsule is what sticks.
Dougsim · CC BY-SA 3.0 · Wikimedia Commons

What goes wrong

The 3.0L 6G72 V6 petrol PD Space Gear is prone to overheating specifically under load - climbing hills or towing - while sitting normal on the open road. The usual culprits are a thermostat stuck closed, a tired water pump, or a partially clogged radiator that no longer sheds heat from the tall, heavy van. Owners frequently find the fault appears right after a coolant change or timing-belt job, pointing to trapped air or an incomplete bleed. The aftermarket sells full-alloy performance radiators for this engine, which itself signals how commonly the original cooling capacity is marginal on these vehicles.

What you would notice

Temperature rises when climbing hills or towing but is fine on the flat
Overheating that began shortly after a coolant change or timing-belt service
Coolant loss or bubbling in the expansion bottle
Heater blowing cold at idle after a top-up (trapped air)

How to check it

Where to look. Engine bay - thermostat housing, water pump, radiator and coolant expansion bottle

Drive or load-test the vehicle and watch the temperature gauge under load such as a hill; check the thermostat opens and the radiator warms evenly across the core; inspect the water pump for weep or bearing play; confirm the system has been properly bled with no trapped air; look for a clogged or previously repaired radiator.

Parts involved: Water pump, Thermostat, Radiator.

What it costs to put right

$400 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

“Does the temperature stay steady when towing or climbing a long hill?”
“Have the thermostat, water pump or radiator been replaced recently?”
“Did any overheating start after a coolant change or timing-belt job?”

Now check the Mitsubishi Delica 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 Delica Owners Club UK forum thread '3l V6 Petrol - Overheating?' (mdocuk.co.uk/forums)
JustAnswer '6G72 engine overheating under load' case (justanswer.com/car/fjtkc)
Fenix Radiators 'Mitsubishi V6 Delica Full Alloy Performance Radiator' (fenixradiators.com.au) - aftermarket upgrade for marginal 6G72 cooling

Mitsubishi Delica buyer questions

Is 6g72 v6 overheating under load from thermostat/water pump/radiator serious on a Mitsubishi Delica?

We rate it major and common on the Mitsubishi Delica. The 3.0L 6G72 V6 petrol PD Space Gear is prone to overheating specifically under load - climbing hills or towing - while sitting normal on the open road. The usual culprits are a thermostat stuck closed, a tired water pump, or a partially clogged radiator that no longer sheds heat from the tall, heavy van. Owners frequently find the fault appears right after a coolant change or timing-belt job, pointing to trapped air or an incomplete bleed. The aftermarket sells full-alloy performance radiators for this engine, which itself signals how commonly the original cooling capacity is marginal on these vehicles.

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

$400 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 Delica years are affected?

Our research records this fault on the 2000–2006 Mitsubishi Delica. 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.