We have built a Turbo 6.0 that is reaching temps of 217 and the expansion tank is bubbling and spilling water out once we reach 210, we're running a all Aluminun mishimoto 240sx radiator and a brand new water pump. And the radiator lines seem to have a lot of pressure in it. We ran the same setup on an 5.3 and never had issues.
Could there still be air in the system or do I need a bigger radiator or maybe bigger expansion tank, Any help would be useful right now thanks!!

 

Are you running pure water? Shouldn't boil at 217 even at 25% coolant

 

217 degrees isnt enough to boil the coolant unless youre running straight water. excess cooling system pressure and bubbling are good indicators of a lifted head and or a bad headgasket.

 

It's been filled up with mostly distilled water not much coolant.

 

It has brand new LSA Headgaskets and and brand new ARP Studs engine has less than 700 miles on the engine I really hope it's not lifted head or head gasket

 

Could be air, which to get air out you might need to just idle and raise front wheels very high to help burp the system. You checked oil and no chocolate milk?

 

one simple and easy thing to check is the thermostat. are the fans turning on? id pick up a 5 gas analyzer and check for combustion gases in the coolant system if you cant find anything else.

 

Yes I have checked the oil it's pretty clean and doesn't at all look milky