Hi I have a 2004 Denali that when in drive thru or parked over 10min starts to get hot. ac will start to blow warm air and the temp will start to go over 210F.
I have replaced radiator. Water pump and thermostat with housing also the
fan clutch
while driving all is great ac nice and cold and engine at normal temps idles great still as well.
Same problem, first summer with my Z71. My tuner raised idle to 750RpM.
It worked for that summer. Before next summer came, deleted the mech clutch fan.
Replaced the mech clutch fan with a pair of electrical fans, tuner adjusted for them,
now it can idle in the hot sun all day with cold AC at 600RpM in Drive.
If you've misconceptions about tuning, an old GM TSB adds an electrical fan that
blows when the AC is demanded.
But electrical fans and tune are more fun, get better MpG, and will help my Z71 last longer ...