Nissan Repair: nissan d21 2.7 td, nissan d21, thermo fans

Question
hey i have a 96 duel cab 4x4 navara which has had a d21 2.7 td put in it. which runs fine except when on the hiway after about 30min at a 100klm it will over heat. i have replaced the water pump and had the radiator flushed and also taken out the thermostat and installed two thermo-fans but i still have the same problem it also overheats when its working hard like in soft sand. do u no what could be making this happen? please help

Answer
Jarred,

It could be that it is running lean and that could cause the problem when it is being loaded like you describe.  I would check the fuel pressure at idle and while it is under a load.  Another item that could cause the problem is when it is loaded could be too much boost.  Check to make sure you are getting proper boost.