I have a 2004 3 litre Patrol. I have been travelling around Australia now for 4 years with my wife and kids towing either a large off road camper or our 19ft full size van. The car has never once let us down (other than a cracked chassis fixed by ATOC) and has been through hell and back. At Christmas I made a few cheap engine modifications that have made a huge difference.
I had a 2 1/2 inch free flowing exhaust installed. No cat/air purifer, just a straight through ceramic coated dump pipe and a straight through muffler. I then put an 8" electric fan on the intercooler sitting on top of an alloy plate with a hole cut for the fan. It runs constantly while the engine is running. I also blocked the EGR, added a Dawes and needle valve, removed the inlet manifold and cleaned out the black tooth paste like gunk.
Now here is the facts
. There is a noticable increase in power and responsiveness. While that is nice, it gets better. The biggest improvement is with the EGT. Cruising with the van or camper at 100 km/hr the EGT always sat at around 500-550 (spiking to 600-650 on big hills). Now it sits around 450-500. But the biggest difference is how rapidly the EGT now drops. It literally drops in front of your eyes, just by taking your foot off the throttle slightly.
When we pull up I always wait for the EGT to drop to at least 250 before turning off the engine. That used to take at least 5 minutes to achieve. Now the temp drops to 250 within a minute. The difference is amazing. The intercooler is now only warm to touch after a long run, compared to very hot prior to the fan being installed. I have also noted an influx of butterflies and leaves in the scoop that have never been there before. Clearly we are now sucking in tons more air.
And the very best part is how cheap it all was. Intercooler fan $100-00. Blocking EGR and installing Dawes valve + needle valve, around $100-00. Getting inlet manifold removed, cleaned, new gasket and replaced, $340-00. Yes you could do this yourself but it is a bit of a job. I thought it was money well spent. The exhaust by Fat Pipes in Brisbane cost $550-00. What a bargain. So for a total of $1,100-00 I believe I have a better running engine, and a much cooler engine.
I already have a catch can that catches very little, clean the MAF sensor every 10,000kms, a second fuel filter/ water trap and change the oil every 5,00kms.
I have been adding 2 stroke oil to the fuel at a 200/1 ratio as well as deisel fuel additive for 12 months.
Have I noticed a difference by adding the 2 stroke. Not really but it can't be doing any harm. Any lubrication has to be good.
These are a good truck, and the 3 litre is a good engine. I believe these few mods are money well spent and will hopefully ensure the old girl remains reliable for years to come.
I would like to thank this forum and one member in particular for all the advice, especially regading the EGR block.