You need to be more specific on the trucks behavior. My new truck takes that long too from a fresh cold start. Now if you said that it only blows warm or hot under acceleration and cools down at a standstill then you have low anti freeze level and air in the system.
Yes it is warm during acceleration and cools when I am coasting down a hill or at a light. I Do take my truck into the dealer for the oil every 4-5k miles they check the levels of all my fluids and it checks out okay...
yeah the VQ motors have a problem with getting air trapped in the heater core, when you are accelerating it forces the air out of the heater core and you get heat and when you stop it settles back there again. just overfill the coolant res, as said, one night and it will force the air out and you should be good. its hard to keep up on this since your res will still say full when really you are low and there is air collecting in your heater core. no dealer needed for this, i've had it on my z and my frontier (much worse on my z)
Yes, what they said. My truck will do this on it's own every so often without any air leaks because all the hoses are new. There is a bleeder valve on the firewall and the overflow tank trick works too.