Mitsubishi Problems

This is a pretty common type of question these days. Once cars are out of warranty (and often before that time) many owners elect to use an independent workshop for their servicing rather than a dealership. But some non-dealership workshops don’t always know the little tips and tricks including how to switch off the service reminder after the scheduled service has been performed.

But here’s something you can try at home which should cancel the service light on your ASX. Turn the car’s ignition off. Now press the info button (down low on the dashboard near the steering column) until you see a small spanner icon appear in the info panel on the dashboard. Now hold down the info button until the little spanner symbol starts flashing. Once it’s flashing, release the info button again and the word `clear’ should pop up next to the spanner icon. With `clear’ displayed, press the info button one more time and you should be done. Now start the engine to make sure the service reminder light has gone out. If none of that works, a Mitsubishi dealership should be able to switch off the light for you.

In many cases like this, the clutch is the culprit. The problem appears as though it’s the gearbox at fault, but the reality is that it’s the clutch not releasing properly that is preventing you shifting gears cleanly and easily. When the clutch is either worn or out of adjustment, it can remain partly engaged even when your foot is fully on the clutch pedal. When that happens, the gears can be very difficult to select.

Try this: The next time a gear becomes hard to select, turn the engine off and try it again. If the gear suddenly slips into place easily, then you’re probably looking at a worn clutch or one that is out of adjustment. Poor adjustment can be the result of low clutch fluid levels (in a vehicle with a hydraulic clutch) or a cable or linkage that is poorly adjusted. Your vehicle has a hydraulic clutch, so a leak from either the master cylinder, slave cylinder or any of the plumbing could have allowed the fluid level to drop to the point where the clutch is no longer disengaging fully. This is precisely where I’d start looking in your case.

Remember, however, that while a worn clutch might be the most likely cause, that doesn’t rule out a problem with the transmission internally or a problem in the gear selector mechanism.

Both the petrol and diesel versions of the 2018 ASX used a timing chain rather than a toother rubber timing belt. That means both engines’ timing chains should be good for the life of the engine, although in practice that hasn’t always been the case and some engines do, in fact, need new timing chains if wear develops in the chain or its tensioners. Neither Mitsubishi engine has thus far demonstrated that trait, however, and it’s far less common if the engine has been serviced correctly.

The task of the timing chain or timing belt is exactly the same: They take drive from the engine’s crankshaft to the camshaft and, in the process, keep all the moving parts in harmony. Many car makers moved away from a timing chain to the rubber, toothed drive belt as a way of simplifying engine design and driving down the cost of each engine. The rubber timing belt is also quieter in its operation and is also less prone to stretching (as a timing chain can) so the camshaft stays in perfect synch with the rest of the engine’s rotating parts. It’s a simpler design because it doesn’t need to be tensioned via oil pressure from the engine as many timing chain systems are.

The timing chain, meanwhile, is preferred by some manufacturers because it should last the lifetime of the engine and never need replacement. This isn’t always the case, however, and some engine designs from a variety of manufacturers suffer problems in this regard. But, in a properly maintained engine of sound design, the timing chain should never need attention, while the rubber timing belt generally requires periodic replacement, typically between 60,000 and 120,000km depending on the manufacturer.

Rather than concentrate on a particular brand, the best advice is to find a vehicle with a full service history and signs that it has lived an easy life. Too often, commercial vehicles like vans are bought by their first owner and used and abused. They’re nearly always purchased with a job in mind, and that job can often wreck them or at least shorten their lives.

Sometimes, the down-time associated with proper servicing means that maintenance is skipped, other times the sheer weight of the cargo being carried puts a lot of strain on mechanical components. A van that has been used by, say, a pool chemical company might have been exposed to highly corrosive chemicals every day of its life and could be hiding lots of rust. Even a florist’s van might have every nook and cranny filled with potting mix, waiting to become damp and start the rusting process.

Another good idea is to buy a van that has already been converted to a camper. This conversion is not an inexpensive process, so letting the previous owner spend the money is a terrific concept. Keep an eye on the classifieds for a van that has done a tour of duty with a grey nomad or van-lifer, and is now up for sale as the owner moves on to something new.

This sounds like a classic case of worn synchromesh rings inside the gearbox. These rings are designed to make smooth, easy shifts between gears but as they wear (or even break) they lose that ability and the gears become difficult to change. It’s also common for this problem to be worse on downshifts compared with upshifts which is why you can shift all the way up to fifth, but have trouble coming back down through the gears.

My money is on third-gear synchromesh being your problem. By shifting from fourth back to second and then third, you’re effectively `borrowing’ the second-gear synchromesh to soften the shift into third.

Unfortunately, the fix is a gearbox rebuild. But before that, it would be worth changing the oil in the gearbox and checking out a gearbox additive that helps with shifting feel and smoothness. If that makes a difference, great, but you may still ultimately be looking at a new or rebuilt transmission.

The other thing to know is whether the gearbox is reluctant to select reverse gear with the engine running. If it is, you might instead be dealing with a worn clutch which is much cheaper to replace.

The sound of air hissing on a turbocharged engine is often down to a leak in the intake trunking that takes air from the turbocharger, through the intercooler and into the engine. As this air is under pressure (from the turbo) you’re likely to hear it above the rest of the engine noise. If it’s only a small leak, you might not notice the fall-off in performance (or boost as you’ve described it) but it will only get worse as the damaged part of the trunking deteriorates further. Eventually, you’ll start to feel the leak’s effect as it allows more and more air to escape rather than being forced into the engine.

Checking the boost pressure with an accurate gauge will tell you if any boost is going AWOL, as can an electronic scan which might throw up a low-boost fault-code. But if you can hear the noise and have found the leak, replacing that section of plumbing is the logical first step. If that makes the noise go away, you’ve solved the issue.

Sometimes the leak is down to a split in the trunking, other times it can be as simple as a clamp that has been loosened by the constant pressurisation of the system every time the turbo boosts up. But it needs to be fixed as it can throw the air-fuel mixture way off target and lead to internal engine damage. If you can’t find the leak but suspect that there is one, a specialist workshop can perform what’s called an EVAP smoke test where the intake tract is filled with smoke. At the point where the (visible) smoke escapes, there’s your leak.

Perhaps the clue here is that the problem only occurs when the fuel level reaches one-quarter or less. That suggests that there’s a problem with the fuel pick-up in the bottom section of the tank. Typically, this will involve a split in the fuel pick-up line.

When the tank is full of fuel, fuel covers the split, allowing the pump to pick up fuel normally. As the level falls, the split is exposed and suddenly the pump is sucking air instead of fuel.

Alternatively, your problem could be bleed-back of the fuel pressure when the car is parked, but that would potentially affect things regardless of how much fuel was in the tank at the time. Unless the bleed-back is being caused by the split we’re talking about, in which case you’re back to square one. Either way, it would be wise to check pump pressure and delivery rate (litres per minute) to see that the pump itself is working properly and at correct capacity. Don’t rule out something like a blocked fuel filter, either, which can seriously reduce the flow of the fuel to the engine; critical in any cold-start situation.

Sludge build-up in oil is definitely an engine killer. But with a full and correct service history, this really shouldn’t happen. That it does, is possibly down to long service intervals (driven by consumer demand for less maintenance and down time) and possibly even the way the vehicle is used. If it’s worked hard (towing, for instance) in high ambient or dusty temperatures, then sludge can build up as a natural result. The way a modern turbo-diesel recirculates some of its exhaust gasses also mean soot can combine with oil vapours from the crankcase to cause a build-up of black gunge, and that’s not good either.

I’d be keen to see what the oil analysis shows. If the oil was lacking some of the additives it needs to keep a diesel engine clean, then that may show up.

If you can prove the service history to Mitsubishi’s satisfaction, I’d be asking for some kind of help in the cost of repairs. Whether or not the company plays ball is debatable, but it would definitely be worth a try with low mileage like this and documentation of correct servicing for all of its (short) life. If the vehicle is still under the factory warranty and you have a full service record for it, then it’s pretty clear you have a valid warranty claim, barring any negligence or mis-use on your part.

Mitsubishi’s manual gearboxes from around this time (and earlier) were some of the noisiest around. But usually it wasn’t anything to be concerned about. Bearing rumble and some clutch bearing noise were pretty much par for the course, but your problem sounds more like it’s associated with the gearbox’s synchromesh rings. These rings are designed to allow the gearbox to slip between ratios smoothly and silently, and any crunching noises during shifts can often be traced to worn synchromesh parts.

The good news is you won’t harm the transmission by continuing to drive it, particularly if you’re careful and take your time with the shifts you know are most likely to create a crunch. If you can live with that, fine. If not, the gearbox will need to be removed from the car and rebuilt. That will be neither cheap nor simple.

It all depends on whether you have the petrol or turbo-diesel version of the Triton, Jeff. If it’s the more common turbo-diesel engine, it’s fitted with a timing chain which should last the life of the engine.

But if you have a very late-2018 build example of the Triton cab-chassis with the 2.4-litre petrol engine, then it will be fitted with a toothed timing belt which should be replaced at least every 100,000km.