Mitsubishi Problems

If the engine is running well, but the car won’t move in gear when you take your foot off the clutch, it’s very likely that your clutch has failed. The clutch is responsible for transferring power from the engine to the gearbox and, if it wears out, it can no longer do so and the vehicle will just sit there and not move even when you take your foot off the clutch pedal and the car is in gear.

You noted that the car had previously seemed to lose power, but this was more likely to be the start of the clutch failing and not transferring all the power it should have been. Eventually, though, the failure became total and no power is getting through to the gearbox (and, therefore, the wheels).

A new clutch is the likely fix but make sure to check the flywheel for damage and wear while the car is apart.

Blow-by is a normal part of engine operation, particularly turbocharged engines where the combustion chamber pressures can be extremely high, forcing gasses past the piston rings and into the crankcase. Excess blow-by, however, suggests that there’s perhaps an overboost problem, wear in the engine or that the ventilation system designed into the emissions controls of the engine is not working properly.

The crankcase ventilation valve would be a good place to start checking as these can become very dirty and even clogged over time in a diesel engine, and a compression test of the engine might tell you more as well. The first thing to do is find another vehicle of the exact same make and model and see if it, too, has a similar level of blow-by in evidence. From there, you can decide which way to go, but either way, a good diesel mechanic should be able to identify the problem accurately.

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.

The ASX was launched in Australia in 2010 and from the very start was offered with a CVT transmission, as well as a conventional manual transmission, depending on what specification you chose. The ASX’s CVT differs from some by having six fixed steps which makes the car feel and sound a little less alien to drive, but also potentially sacrifices a small degree of efficiency. That’s because the CVT is most efficient when allowed to use an infinite range of just-so ratios, rather than the six fixed ones Mitsubishi specified.

What you’re probably hearing is the pump switching on to prime the engine’s fuel system so that it starts easily and promptly. Even though the engine isn’t running, when you switch the ignition on, systems like the fuel pump all come to life to get things ready to be started and driven. When the pump has generated enough fuel pressure and volume to start the engine, it can then switch off and only switch on again once the engine is running and a constant supply of fuel is required. This could be why it only runs for a few seconds when you first turn the ignition on.

This is pretty normal, but what isn’t is if the pump starts to make a new noise or the tone of its buzzing changes. At that point, what you might be hearing is wear or damage inside the pump.

This is definitely not the sort of information car makers publish. Instinct suggests the headliner should, indeed, fit through one of the door openings, as that’s how it would be fitted on the production line. Try a front door opening first with the front seat slid all the way back and the backrest laid right down.

The other option would be to politely ask a motor trimmer how they manage this job.

Some of these east-west mounted V6s can be very difficult to access the rear bank of cylinders. A quality workshop manual will detail how to remove the rear rocker cover and spark plugs, and there are also some very good online tutorials you can tap into.

The fact that no error codes have been logged suggests that the spark plugs are at fault. In some cases, on-board computers can detect a bad ignition lead or coil, but will not recognise a dud spark plug. But oil leaks can also cause misfires if the oil gets into contact with the leads or spark plug contacts, too, so the leaks need to be fixed as well. The spark plug theory is also supported by the fact that the miss is occurring under load, which is when an ignition system is working its hardest.

This sounds – on the surface – very much like a problem with the car’s body computer. The body computer controls all the electrical functions you’ve just listed as well as potentially being responsible for controlling the immobiliser. If the computer isn’t telling the immobiliser to switch off, you could easily find that the engine will turn but not fire.

It doesn’t work every time, but one way to reboot the body computer is to disconnect the battery and leave it overnight. This will sometimes restore the computer to factory settings (for want of a better term). If the computer is on the way out, however, this reboot may not be permanent. The other thing to check is the battery inside the ignition key. A flat or weak battery here can also mean the immobiliser doesn’t switch off and the engine will refuse to start. If none of that does the trick, an auto electrician is your best bet.

From memory, this model Triton featured a dual-mass flywheel. These were fitted to smooth out the engine and make gear changes quieter and smoother. But when they fail, they can produce the sort of symptoms you’re hearing.

Instead of a one piece, solid flywheel, the dual-mass unit is made in two parts with flexible couplings between them. These couplings absorb some of the shock of gear-shifts and engine vibrations, but when they’re worn out, the whole assembly becomes `loose’ and starts producing clunks and bangs. Replacing the flywheel is the only fix, but make sure you replace the clutch assembly at the same time. Some companies also offer a single-piece flywheel conversion for this vehicle to prevent the problem occurring again.

There wasn’t a recall for this problem on this model, but there was a service bulletin (like a recall but for a non-safety related issue). The problem was the same as yours; examples of this diesel engine were overheating. The cause was deemed to be a loss of coolant and was related to poor cylinder-head gasket sealing. In turn, that was deemed to be the result of a too-rough metal surface on the cylinder block where it joined the cylinder head and sandwiched the gasket.

Mitsubishi introduced measures such as a different coolant concentration, a different radiator cap and an ECU that gave more warning to the driver. But none of these things actually fixed the issue with the head gasket and the metal surfaces. In fact, it wasn’t until 2014 production that Mitsubishi changed the machining process on the production line to give a smoother head-gasket sealing surface which solved the problem for good.

It seems that some engines had problems while other simply did not. Hard use such as towing heavy loads or driving at sustained high speeds made the problem more likely to surface.