Mitsubishi Pajero Engine 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.

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.

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.

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.

It's not unheard of for a brand-new component to be faulty straight out of the box. However, the more logical explanation for your car refusing to start after the crank angle sensor was replaced is that the sensor was not the problem in the first place.

Instead of continuing to replace random components that may or may not fix the problem, you really need to find the problem and then tackle it with new parts. Scanning the car's electronics will often throw up the answer, but it could also be something as simple as the car having sat for a few months and the fuel going stale in the process. The causes of a no-start condition are endless.

The Mitsubishi Pajero is actually regarded as a very reliable vehicle, so your experience is not typical. There are several potential causes for this, but the thing I’d check first would be the air filter. Is it possible this was overlooked during the recent service? A blocked or dirty air filter will certainly make an engine blow smoke and operate poorly.

I’m assuming your vehicle is a diesel, so it would be worth checking the suction-control valve on the back of the fuel pump, too. Also, a stuck injector that is pouring fuel into the engine can also potentially create these symptoms. I’ve also heard of the Pajero diesel suffering from a build-up of black gunk inside the intake system that can also cause symptoms like the ones you’ve described.

Engines are amazing things, Renee. Neglected, they can fall to bits in a surprisingly short space of time. But treat them properly with the correct preventative maintenance and you’d be surprised how far they’ll go before they wear out.

What you haven’t told me is whether your vehicle is diesel or petrol powered. That said, both the diesel and petrol engines fitted to this model Pajero are well regarded in the trade and capable of going the distance if, as you claim, the servicing has been by the book. Over the distance you’ve quoted, I’d expect the diesel to have needed possibly a new turbocharger and definitely new fuel-injectors, while the petrol V6 can cover this distance without any major work.

But while the engine might, indeed, have lots of life left in it, what about all the other components? The brake rotors, shock absorbers, transmission and many other intrinsic parts of the vehicle wear out, too. So, just because the engine is fit and healthy, doesn’t mean the rest of the car will be so tip-top and ready for another 300,000km.

I don’t believe that what you want is out there, and can only reiterate past advice, buy a Patrol/Pajero/Prado/LandCruiser.

In the old days we would never have left home without a spare fan belt in the boot and the tools needed to change it on the side of the road. I'm actually surprised that a fan belt, being a consumable, would be covered by the warranty at all, but as they you say they agreed to cover the cost of replacing it I would approach Mitsubishi directly through its customer assistance people and request a refund of your money.