hey all. i did a 6.0 swap into a 98 suburban last jan and every thing has been good up till about a month or so ago.

i have removed the stock fan and clutch assy and am using a set of camaro fans, and i have also swapped the stock radiator for a 4 core out of a 454 truck.

it does not overheat it traffic or running arround town. it starts to get hot at hwy speeds after about 45 min to an hour at speed. i can slow down about 3 to 5 mph and it will cool off a little or i can turn the heater on and do the same, then it is fine for about 30 to 45 mins.

i had a weater hose that was sucking closed that i thought was the problem but that was not it.

any advise would help.