Coolant bubbling, overflowing out of overflow tank

Well my truck has the v6 and has heater hoses above the radiator, this I do know and this OP has the v6 not the 4 banger, hehe

 

It sounds like the radiator is marginal. I have a post titled "Radiator basics" where I show picture of the top of the radiator that had the exact symptoms that you are experiencing.

The balance of the system works as designed. The radiator cap holds pressure and then purges when the pressure exceeds the cap design and when the system goes into vacuum it pulls the coolant back in. The fan/clutch mechanism is for cooling below 20 mph-ish where there isnt enough air flow through the radiator core at low speeds to cool the system.

 

4 bangers have similar hose setup as in heater hoses are higher than radiator and I have had no problem with air in the cooling system/air purge. I have seen T splices done to heater hoses cause head gasket failure and asked the owner what/why? Owner said he was told because the heater hoses are higher than the radiator and wont flush/air purge without them. Cheap plastic fittings auto parts store sold along with flush and fill kits and wrong coolant $75. Head removal, resurface, gaskets, labor $1200.

 

For cooling the engine would it help to run one of those oil filter sandwhich adaptor plates and run your oil thru an oil cooler, to pull excess heat out of engine, seems like running over 6psi of boost generates a ton of extra heat and this could be another way to remove heat. #Air cooled water cooled oil cooled....* mine pushes coolant back and forth on long hill climbs (10- 20 min) even though rpm's are around 3k rpm

 

Ive recently started having this issue. Coolant boils out of reservoir only after slow uphill offroad climbs. Long highway drives even over mountain passes, idling for long periods of time in 100+ desert heat, even tried holding my brakes slightly going up steep paved roads and no issue. Seems to only happen when im going slow on uphill and rough sections of trail. Coolant continues to boil over several minutes after engine has been shut off