So i recently purchased a 1999.5 Pathy 4x4 with just under 90,000 original miles. Bought it from the 2nd owner, who used it only to tow his boat to a lake a couple miles from his house 4 or 5 times a year. The original owner used it strictly as a third vehicle, and had only driven it 76k in the 10 or so years he had owned it. The truck is in really amazing condition and is bone stock with absolutely no modifications except upgraded rear shocks. It runs amazing and I'm really very happy with the purchase ($5200) with the tow hitch and a nice trunk liner. The 2nd owner had to replace a fuel injector and subsequently the catalytic converter because he drove with the malfunctioning injector for a while. My question is, I am 95% sure that the timing belt / water pump have never been replaced partly because I have what i was told are all of the service records for the life of the vehicle, and it hasn't even hit 105,000 miles, which is when the service book says these parts should be replaced. Due to to year of the vehicle, do you guys think I should go ahead and have these changed (or at least inspected?). I am currently in the bay area of Northern California, but by this time next month, my wife and I (and my pathy) will be living in or around Kona Hawaii. So we will be using it for 4wd pretty often to access the lava roads to nearby beaches. Thanks in advance!!!
Nathan

You can't inspect it without taking off the covers, so at that point, you mind as well replace it. That said, the timing belt is rubber and can dry rot. Twelve years, IMO, is taking your chances; I recommend replacing the belt every 6 years if it doesn't meet the mileage interval at that time. Not only would I replace the water pump, but also the tensioner pulley and front seals, thermostat and drive belts. Gates makes a really good timing belt and componant kit which you can purchase at Rockauto.com at a great price. The rest of the parts I would get from Nissan. 1stAAANissanparts.com has really good prices and service.