Let's be honest, the reliability issues surrounding the ZD30 turbo-diesel engines in GU Patrols have been talked about endlessly over the last few years and are pretty well known. While some people have had terrific service from the punchy four-cylinder donk and enjoy the decent amount of power the revvy motor puts out without a worry, others have not been so fortunate.

Problems with certain sensors and boost levels are woefully common, and a disturbing amount of Nissan owners have fallen victim to the dreaded 'holed piston' that seems too often result from these inherent shortcomings. Paul Waning was one such person. After buying the Patrol back in '08 to tow his Goldstream camper trailer to his favourite camping destinations, the modified engine unexpectedly decided to let go, leaving him with a dilemma.

Despite the setback, Paul still loved his truck and wasn't keen on getting rid of it. And with good reason too – the big Nissans are well known for having one of the best drivetrains in the business and the roomy wagon suited Paul and his family perfectly, so a replacement engine was the only option.

While a dirty great V8 would have been nice, the associated fuel costs would have been horrific, so an oil burner was pretty much Paul's only choice. Given that he didn't want to be mucking about with one-off parts and grafting in foreign componentry, a Nissan diesel narrowed the field even further, but there was no way he was going to throw another hand grenade at his pride and joy. So, the venerable TD42 six-cylinder motor from a 2005 Patrol was settled on, and the truck delivered into the capable hands of the boys at Cross Country 4x4 near Adelaide.

After a couple of weeks of vigorous spanner spinning and welder work, Paul's truck emerged with a new heart beating in its chest and was once again ready for towing and off-road duties, only now with a whole lot more reliability.

Not wanting to settle for less power than he had at his boot soles previously, Paul also had a turbo and intercooler fitted to the big six along with a 3in mandrelbent exhaust that gives an aggressive note and lets the ZD30 owners know that the Patrol is now blowing by on the track that this truck means business.

It may have taken a little longer than originally planned, but with the upgraded engine, tough barwork and heavy-duty suspension, as well as a host of other trick mods and touring accessories, we reckon Paul has finally got his GU just right.

UNDER THE BONNET

The original engine under the twin-scooped bonnet of Paul's wagon was the 3.0L turbo diesel four-cylinder motor that seems to have been the cause of more frowny faces than the ATO. Despite being modified with a Steinbauer chip and 3in exhaust, as well as an oil catch can (which supposedly remedies a lot of the common problems), it still managed to burn a hole through the number-one piston at just shy of 200,000km.

Not to be deterred by this, though, Paul let his fingers do the walking and got onto the guys at Cross Country 4x4 in SA and commissioned them to graft in the 3.0L's bigger, more low-tech (read: reliable) brother, the 4.2L TD42. While the engines come from the same family, they are actually not a bolt-in swap and several things have to be changed.