Mitsubishi Pajero Problems

Provided the blown head gasket is the engine’s only problem, then you can certainly squeeze plenty more kilometres from it by replacing a blown head gasket. It’s a pretty involved process, however, and requires removing the cylinder head, cleaning the surface, and fitting a new gasket. You also need to check the mating surfaces of the cylinder head and the engine block to make sure they’re straight and able to form the seal the engine requires. So, it’s pretty specialised work.

The wild card comes in the form of what else is wrong with the engine. If it’s worn internally and burning oil, for instance, it might not be worth spending the money to change the head gasket. In that case, a full rebuild or a replacement engine makes more sense.

From memory, the centre orange light on this vehicle indicates whether the locking centre differential is engaged or not. When the light is on, the diff in engaged. When it’s flashing, it’s in the process of engaging electronically. For this process to occur, the main transmission needs to be in neutral, so trying to get the vehicle to move and change gears while the diff is somewhere between engaged or disengaged, might be the problem.

I’ve also heard of problems with the sensor that detects whether the centre diff is engaged or not on this make and model. Sometimes the sensor can die, other times it’s just a wire that has fallen off, but it could mean that the vehicle is confused about what to do and the transmission is stranded in neutral as result.

Try rolling the car forward a few metres (if possible and safe) to see if that small amount of movement allows the diff to engage and normal operation to be restored.

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.

Even when it’s completely empty, your caravan is still likely to weigh a couple of tonnes (give or take). At which point, you’re using a fair chunk of the Pajero’s towing capacity of 2500kg. What’s happening is that the transmission of the car is choosing to shift down a gear or two to bring the engine up to a speed where it’s making enough power and torque to haul the rig along at the speed you’ve chosen to travel at. Maximum torque in the Pajero’s 3.5-litre V6 occurs at 3500rpm, so that’s what the transmission will aim for when you need maximum thrust.

The process also takes some of the load off the transmission, helping it live longer and avoid damage and overheating. There’s a general rule that says you shouldn’t really tow anything remotely heavy with the transmission in overdrive. Experienced towers physically lock the gearbox out of overdrive, and this, essentially, is what the car is doing for you by shifting down gears when a hill or headwind increases the load on the driveline.

The petrol V6 in the Pajero was never a fuel sipper, and I’m not surprised you’re seeing higher fuel consumption in this scenario. This is also the reason many people who regularly tow choose a turbo-diesel to do so.

This sounds like a classic case of a vehicle with a fuel pump that has died. Electric fuel pumps have a very finite lifespan and, when they stop, they do so suddenly, for no apparent reason and with the result that the engine will simply not start or run at all. By spraying starting fluid into the engine, you’re giving it a sniff of fuel; enough to make it fire, but not run for long.

You’re probably looking at a new fuel pump, but don’t forget to check fuses and relays, the lines for leaks and the various fuel filters for cleanliness.

Unless your engine is overheating very quickly and then miraculously cooling instantly, I’d say there’s a problem with either the temperature gauge itself or the sender/sensor unit that controls it.

An auto electrician will be able to test the gauge and its sensor and tell you what’s happening. Scanning the vehicle electronically might also reveal the cause as the onboard computer may have logged this odd reading as a fault code.

This light is designed to warn you that you have the centre differential locked. This diff lock should only be used off-road in limited-grip situations and having the lock engaged on the bitumen will soon break expensive driveline parts. You’d also notice if the diff was engaged as the car would feel very odd to drive with lots of clunks and groans and no desire to be steered normally.

What’s more likely is that the light itself or the sensor that triggers it has a short-circuit that is feeding the wrong information to the body computer which then lights up the warning. By shutting the engine down and restarting it, you’re effectively rebooting the body computer and things go back to normal for a while. An auto electrician would be our first stop.

If by some chance the light is illuminating because the diff lock is, indeed, attempting to chime in, you have a more serious problem as the driveline might well suffer huge damage if the lock managed to actually engage on the highway.

First suspicions would be the body computer which controls all sorts of functions including central locking, indicators, dashboard, heating and central locking. The fact that two functions have disappeared together is what makes the body computer a great place to start.

An auto electrician should be able to diagnose the problem. The worst-case scenario is that you’ll need a new body computer model and will then have to re-sync the new computer to your existing keys. But don’t rule out a poor earth or even a battery that is starting to show its age.

There are literally dozens of reasons the check-engine light might illuminate in a car like the Pajero. Fundamentally, the car is trying to tell you something is not right with one or more of its systems, and that it needs attention. Those systems could include (but are not limited to) the ignition, fuel, emissions, exhaust, mechanical and cooling systems.

Simply replacing random parts is a quick way to burn up a lot of money and still not fix the problem. I’m curious as to why you’ve assumed the problem is with the EGR system. And even if you’re right and the EGR system is causing the problem, you might find the fault is with the actual EGR valve or its coolant system, rather than the electronics that control and monitor it.

Take the car to a workshop and have it electronically scanned to try to narrow down the cause of the check-engine light. The fault codes will have been logged by the on-board computer and are usually the only way to zero in on the actual problem. Even once that’s done and the problem fixed, there’s probably a separate procedure for switching the engine light off.

If it was just the indicators or just the central locking, you could spend a long time figuring this out. But if both the indicators and the central locking went on the blink at the same time, any mechanic's suspicions would be drawn to the body computer. This is an ECU that controls all those functions, including cruise-control, heating and ventilation and much, much more.

If the computer unit fails or starts to behave erratically, you'll notice these functions either working intermittently or not working at all. In some cases, a new body computer will be needed, but you can try this trick at home. Disconnect the battery and leave the car overnight. You may find when you reconnect the battery, all the functions have been restored.

The other trick to try is to hold the lock button on your key fob for a minimum of 60 seconds. That, too, can often reset the body computer and reboot thigs back to where they should be. Failing that, it's off to an auto electrician.