just what i advise, but be careful of screwing up bolts.

 

i recently had same problem with my 4.9. I had the radiator rodded out, flushed system with that prestone stuff, replaced water pump because the guy at the radiator shop said he found metal in the radiator that might have come from the water pump. Replaced thermostat and fan clutch and refilled with coolant. No problems sense. All labor done myself and total parts cost about $150. Good luck

 

What the??? I replaced the radiator (old one was a single core, new one is a 2 core). And it is still running hot compared to about 2 months ago. It has never done this and it isn't that hot here (upstate NY), currently 80, and tonight it was low 70's. I have replaced the rad, tstat, fan clutch, checked that all hoses were clear and clean, and flushed with a prestone kit for about 1/2 hour. The water pump was replaced about 20K ago, it couldn't be that could it? It isn't leaking at all. I can't figure this out. There is no buildup of junk on the AC condenser either to restrict airflow....this has me stumped!!!

 

another thing i did when i went through mine, was to let the engine run with the radiator cap slightly open, like in that first click area, to allow all the air to leave the system. That helped a little bit, it diffenately made it fluctuate less. I would double maybe even triple check the thermostat. When i did mine i thought the thermostat was alright, heck it was only 3 months old, but it was a failsafe and had locked in the open position. And in the open position all the time a truck can still run a little hot.

 

the 302 in my truck had issues with this also. since i did the swap, and put in the HUGE 4 core aluminum radiator, it can be 110 with the a/c blasting, AND sittin in traffic with no worries, it never even reaches halfway. i have a 180 t stat, and a severe duty fan clutch. i got my aluminum radiator from a/c radiator warehouse for 130 bucks