Mitsubishi Challenger Engine Problems

Some Mitsubishi models in the past have had problems with a rough surface on the head-gasket sealing surface of the crankcase,. This has led to head gaket failures and coolant loss. This was fixed by about 2014 with a different machining process at the factory, so this could be your problem.

At the time, Mitsubishi issued a service bulletin for this problem and was modifying cars to fix them. However, whether this bulletin would still apply in 2025 is the big question. However, it would certainly be worth contacting Mitsubishi Australia’s customer service department to see if there’s still assistance available.

Under Australian Consumer Law, all brand-new cars sold here must come with a factory warranty, but it’s up to the manufacturer where to set the time and distance limits for that model. But even the most generous car-maker isn’t going to apply a warranty to a car that is now two decades old and has covered goodness knows how many kilometres.

For reference, most new-car warranties now cover a vehicle for between five and seven years. You will sometimes find a manufacturer will help out with some of the cost of repairs if the vehicle is only slightly out of warranty (and then, usually on a pro-rata basis). And that will only ever happen if the vehicle is question has an absolutely perfect service record.

If your engine has multiple problems, the best advice might be to look for a good, tested second-hand engine and replace the whole thing.

This definitely does sound like a build-up of carbon and soot inside the intake system of the engine. Believe it or not, this is not an uncommon problem and occurs partly because of the emissions controls forced upon engine manufacturers.

The diesel engine in your car features an EGR (Exhaust Gas Recirculation) system which means the engine inhales a portion of its exhaust so that it goes through the engine twice and is burned more completely. That's good for emissions, but it means that exhaust soot is being consumed by the engine via the intake system.

Combine that with the oily fumes from the crankcase ventilation system (which also feeds into the intake) and you can soon wind up with a black, sticky, sooty glug that blocks the internal airways much as cholesterol blocks human blood vessels. In some cases, the only way to fix this is to remove the intake system and manually clean it out. This can be time consuming and expensive, but could easily be why your check-engine light is being triggered.

The other bads news is that this could happen again over time. The solution to that is to fit a quality air-oil separator (also known as a catch-can) which keeps the oil fumes out of the equation.

If the engine runs when you apply some throttle but won’t idle, I’d be drawn to the idle stepper-motor which is a small electronic actuator that is designed to keep the engine at a stable, steady idle when no throttle is applied. It’s a pretty simple fix, but I’d also check things such as fuel delivery pressure and ensure that the ignition system is in good condition, also. Don’t forget air and fuel filters, either, they’re simple things but critical to how an engine behaves. Low battery voltage can also make an engine like the Challenger’s play up at idle, too. Also, have the throttle-position sensor checked. If this fails, it can leave the computer guessing about what the accelerator pedal is trying to tell it.

Is it related to the operation of the fan? If so it could be wear of the fan, and replacing it might be your answer. But you need a mechanic, someone who can actually hear it, to check it for you.

Before you rush off and claim you’ve copped a lemon I would investigate the reason for the problem. I suspect there is a problem with the vehicle rather than an issue with its ability to tow. Have your dealer check it out.

The problem could have been the coolant, rather than the cap. A higher-pressure cap can help if it's a minor problem but, in any case, if you run into problems in the future there is an admission of a problem by Mitsubishi.

It's possible that you could change the system, but I would consult an air-conditioning specialist to get a clearer picture of the differences between the two systems, particularly with components like the compressor, drier, heat exchanger etc.

No, it is not normal, and something is going wrong to make it happen. You should report it to your dealer and request that it's investigated and fixed.

There are three main types of LPG systems: the mixer/venturi system that was very successfully used for many years and which is like a carburetor on a regular petrol engine; the vapour-injection system that operates like the fuel-injection system that's fitted to your car; and the latest liquid-injection system that injects the LPG into the inlet manifold in liquid form. It's claimed that the liquid-injection system is the most efficient and delivers the best outcome, but vapour-injection is claimed by some to be almost as efficient and well proven. Either liquid or vapour-injection from a recognized brand, like Eurogas or IMPCO, is your best bet.