replacing a spot less rad is a wast of money IMO
did you check the temp with the XCal II
and the pressure check is a good Idea
also a 50/50 mix is very important to temp
When it gets hot is the hole system hot or just the engine
do you have access to a non contact Infrared Thermometer i set my Efans with one was right on with XCal II temp
start truck cold the top rad hose should stay cool till the stat opens (if it get hot slowly look at stat again ) onces its hot check temp right at thermostat housing
Good luck

 

I hate dealerships but at this point I would take in and say I dont want it back tell its running right. youve done everything I could think of other then manually checking the water temp

 

again the bottom of my radiator that was replaced was damaged even though the inside was spotless. three cores were crushed and sealed off. i am running 50/50 mix. at this point i am thinking about taking it to the stealership after i try a few things like manually reading temps. other than that i am completely stumped. i was wondering if the cam phasers could be causing it since i am told they control the exhaust side of the engine but was told they would throw a code if they were out of wack. i do have a infrared thermometer. ill see what that reading is as well.

 

225 is not too hot for a modern 90 degree V8. It's pushing it for the trans, but a modern V8 should be able to run at 265-275 max before issues arise.

Hell, the engine (5.0) in my buddy's '66 Mustangs ran at 225 all the time, no issues.

 

Not to ask a stupid question but did you have the radiator replaced before or after this problem started? I only ask this because if there is air in the cooling system it will cause hot spot in the engine and do some serious damage as the coolant becomes super heated steam at the hot spot.

 

after

and yes it will handle a little more heat. but i beleive the engine goes into failsafe at around 220.

 

HA! Not even close!! I have my temp gauge mounted in the heater hose that comes out of the intake just before the thermostat. Should be about the hotest water in the system. I have seen 235 several times with no ill effects. Fail safe mode, I've heard, kicks in somewhere north of 240.

FWIW, the stock temp (idiot) gauge reaches its parked "normal" position around 175-180 and at temps as high as 235 on mine the stock needle never moved. I don't know how hot it has to get before the stock temp gauge shows a hot or above normal condition.