I'm gonna make a long story short. I bought a 2019 WK2 5.7 (Tow Package) with 47k on the clock. Dealer changed water pump prior to me buying, but after a few days of owning I returned with cooling issues. Dealer replaced both heads and 4 lifters while they were in there.
I got it back a few weeks ago and I have to say it seems to run hotter and with wider fluctuations that any engine I've dealt with.
What I've noticed: (1) The thermostat doesn't seem to open up until 215f after start up. (2) the fan (controlled by pcm) doesn't kick in until at least 226f (even with AC or defrost) and shuts off when temps come down to 215f, and does that cycle every 2 minutes or so. (3) The engine stays between 215-228 in city driving and it fluctuates fast; (4) on the highway or roads without stops, coolant temps bounce all over the rage between 204f and around the low 220s depending on how hard I'm getting on the pedal.
The video linked demonstrates the idle activity after about 30 minutes of mixed driving.
Maybe I'm just on high alert, having just plunked down good dough for a very suspect vehicle at this point. But those heads had to blow for a reason and I'm looking for peace of mind before the CPO max care is up.
So, am I paranoid or is this just normal?