The best thing IMO is to monitor your exhaust temps with a guage and an alarm. The Autronic digital ones are fantastic as you can set them to set an alarm off at a certain temperature and also a warning light.
You fit the probe into the exhaust system and run it as normal and see what temps YOUR engine runs at. Then, set the alarm to go off 100deg higher than that.
It also helps when you are towing a camper as the temps can get up there on hills etc.
For the 3L patrol, like lots of diesels, a mandrel bent exhaust and dump pipe get rid of the gases faster and can help them run cooler so every bit of help is good.
For the sake of argument there are enough out there that have overfuelled and died that its worth making the effort IMO.