300, 400 its been thrown around for years, but as stroker mentioned todays oils dont break down at temps as fast nowdays
but another good rule of index finger is if you have been working the truck hard, dont just shut her off at 300-400, let her cool down at idle for a few more minutes to help remove as much heat as possible, because when she does shut down, the heat soak will run the temps right back up to 500 or higher depending on how hot its outside and how hard you were working her.
if its a short duration stop, let her idle,
try a few times when she gets to 350 or so
shut her off and walk away, then go look at your pyro temps say about five minutes later, you wil see a good increase, is it enough to cook the oil on the turbo sintered bronze bearing????? only time will tell
if i am doing the stop and go carp i will click on my remote start timer that will run her for 30 minutes, and bump on the high idle, pull the key
lock the doors and go do what i need to do, if i am gone over 30 minutes it shuts off, but if not i get a cold cab and happy truck
