Isuzu D-Max Engine Problems

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 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.

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.

Every all-new MY21 Isuzu D-Max and select current versions of the Amarok and Ranger offer a 3500kg towing capacity maximum - namely all Amarok V6 autos and all Rangers EXCEPT the 4x2 XL Single Cab Chassis Low-Rider 2.2 Diesel at the bottom of the Ford range, and the 4x4 Raptor Double Cab Pick-Up 2.0L Diesel at the very top (they're both 2500kg).

Least torquey is the D-Max at 450Nm, followed by the Ranger (2.2L 4-cyl: 385Nm, 3.2L 5-cyl: 470Nm and 2.0L twin-turbo 4-cyl: 500Nm) and Amarok (550Nm to 580Nm), meaning the Amarok will probably be the least challenged towing a 2.8-tonne caravan. But all three should suffice.

Please note, however, that Gross Combined Mass (GCM) tallies means that there are other weight factors that need to be considered before safely towing a 2.8-tonne caravan, even with a 3500kg ute. These include things like the ute's payload, heavy bull bars, sports bars and side steps, canopies and even the number of people travelling inside. And of course, a fully-equipped and laden caravan can easily exceed the stated tare mass.

We hope this helps.   

D-Max models before MY 17 do not have a DPF. The later Euro 5 compliant 4JJ1-TC engine does have a DPF filter.

There’s clearly something wrong with it. Take it to a dealer and have it diagnosed.

The idle is too slow to maintain running, so check and clean the airflow sensor in the intake, and replace the air filter.

Don’t mess about fit another EGR valve.

It’s clearly frustrating you, but I don’t believe you’ve copped a lemon on the basis of what’s happened. Isuzu fixed the diff, end of story, they also replaced the first pump under warranty, again end of story. The issue is why have two pumps failed, and why didn’t Isuzu cover the second pump. These are questions I would be putting to Isuzu. I’m guessing that the second pump wasn’t covered because the warranty had expired after three years.