Isuzu D-Max Problems

It’s not a problem we’ve heard of occurring in huge numbers, but like any component, a canopy is subject to wear and tear just like any other. Canopies on tradie-trucks can cop an awful hammering at the hands of their owners and damage is inevitable in such cases. Even a few years exposure to Australian levels of UV radiation can cause a canopy to start to break down structurally, so they generally have a finite lifespan.

But instead of replacing the whole canopy (assuming it’s a fibreglass one) it might be worth asking a fibreglass specialist (say, a boat repairer) if the crack can be repaired. That would certainly be cheaper than replacing the whole canopy

This really does sound a bit like a head gasket problem. Even though the coolant and oil aren’t mixing (as you might expect with a blown head gasket) if the gasket blows between the coolant passages and the combustion chamber, the pressure of the engine’s combustion (particularly when the turbocharger is boosting when, say, climbing a long hill) can pressurise the cooling system, leading to the sorts of problems you’re having, including ejecting the coolant all over the place.

But until you’ve done a couple of simple checks, there’s no way of knowing whether there’s a blockage or other problem with the cooling system that is allowing the engine to become too hot. At that point, the coolant will also force its way out of the engine with a similar set of symptoms. A chemical check (called a TK test) will be able to identify whether combustion gasses are finding their way into the coolant, suggesting a head gasket failure., A good mechanic should also be able to tell if there’s a blockage in the coolant system or a problem with the coolant pump.

The last decade of dual-cab four-wheel-drive utes have emerged as the tow-vehicles of choice, and you see them everywhere filling roles exactly like the one you have planned. Popular models include the Ford Ranger you’ve nominated, Toyota HiLux, Mazda BT-50, VW Amarok, Mitsubishi Triton, Nissan Navara and Isuzu D-Max. But there are also cheaper alternatives including makes like the South-Korean made Ssangyong and various Chinese brands like LDV and Great Wall.

Just make sure you know exactly how much you need to tow before making a decision as some of the cheaper models don’t have the same outright towing capacity and even if they do, some of them don’t have the engine performance to make towing as easy as it should be. For parts availability, the Toyota would be king in really remote areas, but any of the major brands are pretty well covered in Australia.

Meantime, don’t rule out ute-based wagons such as the Ford Everest, Isuzu MU-X, Mitsubishi Pajero Sport and Toyota Fortuna. These offer better ride comfort when unladen thanks to more sophisticated rear suspensions and most have as much or almost as much towing capacity as their ute brethren.

The digital displays on modern cars are known to sometimes randomly fail for no apparent reason. Sometimes it’s the whole display that fritzes, other times just a smaller part of the display will disappear. Usually, replacing the LED module is the fix.

From memory, this model D-Max groups the fuel and temperature gauges, odometer and the gear position information into a small unit in the middle of the dash binnacle. Which means it might be a bit complicated re-connecting the temperature and fuel tank sensor units to the new module, as well as making sure the new odometer reads the correct mileage for the vehicle. An auto electrician should be able to handle it, though.

Technically, of course, any car without a working gear-position indicator is unroadworthy, so this needs to be fixed rather than ignored.

This is a tricky one because the D-Max’s SVS warning light seems to be a bit of an all-rounder. That is, it indicates a fault, but a non-specific one. Certainly not one that can be read by the majority of aftermarket scanning tools. Logic suggests there’s something within the driveline that is getting too hot for the computer’s liking, a theory backed up by the fact that it only triggers when you’re towing a big load and the car is working its hardest.

The solution seems to be to present the car at an Isuzu dealership as this may be the only workshop that will have the D-Max-specific scanning gear to determine the cause or even narrow it down.

For the record, the SVS stands for Service Vehicle Soon, but I’m afraid even that’s a fairly generic recommendation and doesn’t get you any closer to the cause. That said, when engine oil or transmission fluid gets beyond a certain temperature, the computer will often detect this and call for a change of fluids as a means of driveline protection. This could be what’s happening every time you tow.

This sounds like a rear differential problem. The differential is designed to allow the inside and outside wheel of that axle to rotate at different speeds (which they need to do as the inside wheel describes a smaller arc than the outside wheel in a corner). If something goes wrong inside the differential, that function can be lost and the wheels try to turn at the same speed in corners. When that happens, the rear end will skip and jump about as the two rear wheels effectively fight each other.

Limited-slip differentials (LSD) often have this problem when the clutches that control the amount of lock-up in the differential fail or become worn. At that point, similar jumping and clunking noises can be felt and heard. In some cases, a limited-slip differential can be restored to health with a change of fluid and perhaps an additive, but in other cases, the unit must be rebuilt.

The rear differential in your D-Max should be the limited-slip type, but around this time, Isuzu made the LSD an option, so it would be worth checking. If it’s an LSD, a fluid change would be the first step towards sorting this problem.

Isuzu lifted the warranty on its vehicles to six years/150,000km for all utes sold after May 1, 2019. Unfortunately, it sounds like your car was on the road in 2018, which means it was covered by a five-year/130,000km warranty. Although you haven’t yet covered 130,000km, the vehicle is more than those five years old so, technically, the problem is not covered by warranty.

However, I think it would be worthwhile contacting Isuzu Australia’s customer service division and pointing out the car’s service history and its mileage. Isuzu may then decide to help with the cost of repairs on a pro-rata basis given the circumstances. It is not obliged to, of course, but it’s definitely worth asking.

Sandy conditions are incredibly hard on every aspect of a four-wheel-drive. The sand itself constantly shifts under the tyres and clings to them as well, dragging them down and making the engine and transmission work very hard to maintain progress. You may have already noticed that you use a lot more fuel in sandy country and it’s all because you need to be constantly making more power to maintain speed than in normal conditions. Turbocharged engines and automatic transmissions, in particular, can get very hot very quickly in sand.

With that in mind, it’s very possible that something in the driveline got hot enough for the car’s computer to go into limp home mode to protect what ever was hot from damage. Limp home mode often involves limiting engine revs and turbo boost, both of which contribute to heat production. This would explain why the car would not climb a crest but came good after a break.

A bit of sweating around the various parts of an engine where one component joins another is definitely not uncommon and not really a problem provided it's not actually dropping oil on the ground (at which point it's a leak, not a sweat-mark). But really, an almost-new vehicle like yours shouldn't be doing this at all.

The rear-main seal on the crankshaft is a likely culprit and a common source of leaks from this area, but since it's a big job (gearbox removal) to do it, I can understand why a mechanic would declare it okay and not to worry. The problem with that is that the sweating is likely to become a leak sometime down the track, at which point you'll have to act.

The good news is that because you've flagged this problem with Isuzu while the vehicle is still under warranty, it's called a pre-existing condition and is covered by the factory warranty, even if that warranty has since expired. However, one would hope that Isuzu does the right thing in the meantime and changes the offending gasket or seal to fix the problem.

Be very wary, however, about Isuzu (or more likely the dealer) claiming the problem is being caused by the catch-can you have had fitted. A good quality catch-can, with a relief valve and correct installation should not cause a rear main seal to leak. As for changing the grade of oil you're using, I doubt that it would do much, but since the alternative is a slightly thicker oil, it might just make the difference you're chasing.