VVT or non VVT heads, can be recondition the same.
The 2UZ is a funny beast when dealing with purging air from coolant system. We must fill radiator and reservoir. Run engine at op temp getting RPM up to minimum 3K for 3 minutes. Turn both cabin heaters to max hot. You should feel very hot heat blowing. If not, you're low on coolant.
Let cool down overnight (8 hr's). Best if parked with front end higher than rear. This put high point at radiator cap. Air move to high point. We must check under the rad cap and top to the neck. If any needed, repeat checking/topping again the next morning.
If thermostat jiggle valve not at top. The system will not properly purge the air.
Cap and thermostat, must both be in proper working order also.
Reservoir hose must go straight down and be clear of blockage.
All bugs, grasses, cottonwood, dust, mud, feathers, etc., must be cleaned from radiator fins.
Once sure coolant is leaking/loss, check all the usual spots for the Toyota red or pink trials. If not found, check ever inch on head gasket. Still loosing, no coolant leak found and oil good. Do a compress test. Then leak down. While doing leak down test or just pressurizing a cylinder. Watch for air bubbles in radiator.
Never use a stop leak! The one time I'd use. Is when head leak is found and cylinder diagnostic show badly scored. I's may the use just buying some time until engine replacement. Which I'd then also replace radiator and pray heat cores not clogged.