frostdragon1

just got done with a full d16z6 build about 700 miles ago(3 months) everything ran amazing. now the past 2 weeks after about 40min of driving it will over heat. ive ran every possible test knowen to man. id dose have all new radiator, thermostat, water pump, radiator cap everything. no visable leaks/puddles anywhere. when it dose over heat the coolant is very slightly low in the radiator. no smoke from the exhaust. coolant system pressure test check out fine. block test came out clean. cylender leakdown test showed good all cylenders. fans run when they are supposed to. it is the weirdiest cooling system problem ive ever seen. every test passes. only over heats about 2-3 days after a top off and with some extensive driving. never on short trips. im getting frusterated. any help is appriciated thanks.

grumblemarc

iTrader: (4)

If you know that it is prone to overheating you are just going to exacerbate the problem by continuing to drive it.
My vote goes to warped head/headgasket. Without any details about your "build" that's all I got.

frostdragon1

build was done right head/block went to the machine shop and all the arp bolt torqued correctly. and as i said the block test showed no exhaust gas in the coolant. no coolant in oil or vise versa. cylinder leak down test passed. the cap tested at 16 psi releasing as labeled....dont know....