Isuzu Problems

Remapping an engine – done right – can provide you with more performance. But there’s also often a price to be paid in terms of reduced fuel economy and increased tailpipe emissions. Typically, there are workshops that are very good at this and others that aren’t so expert at extracting more performance.

But before you go down that route, it sounds like there’s something wrong with your vehicle in its current state. Fundamentally, a 2013 Isuzu D-Max should be able to haul a van of that mass, comfortably at the legal speed limit. That said, that’s a fairly hefty caravan and experience shows that many owners of similar rigs find that about 90km/h is a more comfortable speed for highway travel. So maybe you need to lower your expectations a little.

A full service and tune-up would be the first step in improving the towing situation, by returning all the engine’s settings to their stock position. Modern turbo-diesels can also suffer a fall-off in performance over time as the fuel system (pumps and injectors) wear, the diesel particulate filter becomes full of soot and the intake system becomes clogged with a mixture of soot and oil from the vehicle’s emission-control system. Those are the things we’d check first before shelling out for a remapped engine computer.

I presume your MU-X is a first-generation model, not the second-generation that launched in mid-2021? The latter is engineered for a WDH, but the former is not.

Many people think a Weight Distribution Hitch (and also known as load levelling bars) will alter a caravan’s level or otherwise. But the truth is that these are really only designed to transfer some of the tow-ball loading to the tow vehicle’s front axle. `Level riders’ as they are known are more of the same. Many car-makers do not recommend or even permit the use of these hitches, so Isuzu is hardly alone there.

The problem you face in using them in direct contravention of Isuzu’s own advice is that, if there is a problem on the road, you might find your insurance company will attempt to disown you on the basis of having ignored that official advice.

If we’re talking about the current model D-Max and BT-50, then yes, the entire driveline should be interchangeable. Under the skin, both the Mazda and Isuzu utes are the same vehicle. Car makers enter into joint ventures like the development of this pair of vehicles to keep costs down by sharing the expense of developing, engineering and testing parts like engines, transmissions and, of course, drive-shafts and CV joints.

While most joint ventures like this one will arrive at two vehicles with some visual differences and usually some details differences inside, when it comes to the oily bits, making specific driveline or suspension parts for one vehicle over the other is defeating the purpose of the joint venture in the first place.

Warranty or not, if the workshop that serviced the car broke the cover, surely it’s up to that business to fix it. Separate to that is the fact that the car is still well and truly under warranty, so that makes the problem Isuzu’s to some extent, also.

To be honest, these plastic covers are one of the more useless additions to modern cars and really only serve to make the underbonnet area look a bit neater when you open the bonnet. In fact, they allow packaging engineers to be a bit lazy as they can cover a messy layout. The best advice is to get hold of a new cover under Isuzu’s warranty and store it in the shed. Then, when you’re ready to sell the car, fit the still-new cover so it looks neat and tidy for would-be buyers. The vehicle will run fine without the cover.

I wouldn’t be concerned about the cylinder configuration of a particular engine. What’s more important is how much power and torque that engine makes, and how towing-friendly that power delivery is. By which we mean how smooth and flexible is the delivery. What you don’t want is a peaky engine that needs to be revved before it delivers the good as that puts a strain on everything and make the vehicle tricky and unpleasant to drive.

The good news is that all the vehicles you’ve nominated have good, solid powerplants that are well suited to towing a caravan. Modern turbo-diesels – especially with an automatic transmission – are ideal for this task.

What you should go for, however, is the vehicle with the highest towing rating. In this case, that’s any of the Grand Cherokee, MU-X or older Discovery, all of which have variants that can handle a towed load of 3.5 tonnes. The Everest is almost as good with 3.1 tonne, but only almost. The problem is that the van you’ve nominated can easily weigh between 2.2 and 2.8 tonnes which, with a 3.1-tonne limit, leaves you very little headroom for water tanks and camping gear. You’d be amazed at how much a fully loaded caravan weighs, so don’t rely on the brochure, load the van and take it to a weighbridge to make sure the vehicle you have can legally tow it.

This is not an uncommon complaint with MU-X owners nor the owners of many other makes and models. It seems as though some Bluetooth systems prefer an Apple phone to an Android and vice-versa. The solution for some owners has been to change their brand of phone, but that seems pretty extreme. Others have resorted to aftermarket Bluetooth systems, but since your car is still brand-new, it doesn't make sense to be changing the head unit.

The first thing to do is contact Isuzu to see if there's been a new download to reflash the head unit and improve the Bluetooth performance. Car makers constantly chase this stuff, and a reflash might suddenly make the thing play the game properly.

You can check whether the problem is phone incompatibility by trying to pair somebody else's phone (of a different type) to see if it works properly with the MU-X's system.

Blown turbochargers are hardly an unknown problem on the MU-X or many of the other popular modern turbo-diesel engines that work pretty hard and make lots of horsepower and torque for their capacity.

Some owners report a rattling, metallic noise such as yours; others reckon the sound of a dying turbocharger is more like an air-raid siren. Either way, the turbo needs to be changed sooner rather than later, to avoid the chance of bits of broken turbo being sucked through the rest of the engine with catastrophic results.

Almost certainly not. Unless there’s some strange quirk of manufacturing that allows the mounting points to magically line up, the current Isuzu D-Max is an all-new design, compared even to the most recent predecessor, let alone the model from 2006. The 2006 D-Max shared a lot of its architecture and engineering with the Holden Rodeo and later Colorado, while the new D-Max is a joint venture with Mazda and forms the basis of that company’s BT-50 range of utes.

You may be able to engineer a set of adaptors to mount the early nudge-bar to the later vehicle, but at some point it’ll get messy and simply not worth the time and money investment compared with buying a nudge-bar designed specifically for a 2021 D-Max. There’s also the issue of whether the old nudge-bar design would be compatible with the air-bag system of the new Isuzu. Again, almost certainly not is the short answer.

Conventional wisdom is that an over-drive gearbox (such as your five-speed) shouldn’t tow anything heavy in top gear. The loads placed on the transmission via the over-driven fifth ratio can cause internal transmission damage.

Also, by leaving the engine in fourth gear (locking out over-drive in the automatic version) you stand to have the engine operating squarely in its comfort and torque zone, rather than lugging along in a too-tall ratio.

So that’s the nutshell answer: Save fifth gear for downhills and tail-winds and keep the load off the transmission.

Isuzu switched to a new, Euro 5-compliant engine for the D-Max ute in 2017. To meet the stricter Euro 5 emissions requirements, a DPF was fitted. But D-Maxes before that time do not have a DPF fitted. On that basis, your car will not have a DPF.

Given the problems experienced by owners of DPF-equipped vehicles (not just Isuzus) this is one of the things that has made the older D-Max such a popular second-hand buy.