Mitsubishi Challenger: 4D56 coolant loss and overheating - service campaign 020116 and replaced engines

In November 2014 Mitsubishi ran preventative-action service campaign 020116 covering Challenger and Triton models with the 2.5-litre 4D56HP diesel built before 18 March 2014. These engines could lose coolant through repeated evaporation, particularly after hard work such as towing, and where the top face of the cylinder block was left too rough for the head gasket to seal properly, combustion gases could blow into the coolant and make the overheating worse. The campaign fitted a higher-pressure radiator cap to raise the boiling point and replaced the coolant at 50 percent concentration; Mitsubishi had already changed the engine software in September 2013 to pick up coolant loss earlier, and smoothed the block face from March 2014. A good number of these engines overheated badly enough to be replaced under warranty before those changes landed. On any Challenger of this age the coolant history, and whether the engine in it is the original one, matter more than the odometer reading.

• Coolant level in the overflow bottle dropping with no puddle underneath
• Temperature gauge climbing above normal on long climbs or when towing
• Sweet coolant smell after a hard run, or steam drifting from the front of the engine bay
• Creamy mayonnaise-coloured sludge under the oil filler cap, or white smoke once warm
• A replacement or reconditioned engine turning up in the service history

1. 1

   With the engine cold, check the coolant expansion tank level and look at what is in it - clean green coolant up to the mark, or low, rusty, or freshly topped up with plain water.

2. 2

   Take the oil filler cap off and look at the underside for creamy mayonnaise-coloured sludge, which points to coolant finding its way into the oil.

3. 3

   Ask the seller straight out whether the coolant has ever needed topping up, whether the temperature gauge has ever risen above normal, and whether the engine has ever been replaced or reconditioned.

4. 4

   Ask for the service book and look specifically for service campaign 020116, a radiator cap replacement, or an engine replacement, and ask to see the invoices behind them.

5. 5

   On the test drive find the longest climb you can, watch the temperature gauge the whole way up, and at the top turn the heater to full hot and confirm it still blows properly hot, because a system that is low on coolant usually goes cold at the vents before the gauge moves.

Parts involved: Head gasket, Radiator.

$400 to $9,000 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.

• “Has the temperature gauge ever gone above normal, especially towing or on a long climb?”
• “Has the coolant ever needed topping up between services?”
• “Has service campaign 020116 been carried out, and is it recorded in the book?”
• “Is this the original engine, and if not, why was it replaced and by whom?”

The failure described above is documented in the sources below. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them.

• AustralianCar.Reviews 'Recalls & faults: Mitsubishi Mk.2 Challenger (2009-15)' - service campaign 020116, November 2014
• newtriton.net thread 'Cooling System Service Campaign'
• newtriton.net thread 'Has your MN engine been replaced as a result of overheating?'
• Whirlpool Forums thread 'Triton/Challenger Overheating issue'
• CarsGuide '2011 Mitsubishi Challenger Problems'