I just installed a EGT probe and would like to know how high can the temperature get before I have to start worrying and what should it be before I turn off the engine?

 

you need to tell us more, is the probe pre or post turbo. next we need to know year model. the reason the 04.5 up used a incylinder egr system that kept peak temp very low but egt was 300* higher example a 02 pre turbo would be 1300* max where a 05 would be 1600* but yet the 05 peak temp on the piston is less than on the 02. as far as shut down if you are not towing hard just before shut down do not worry about it. have about 12,000,000 total miles on our fleet of dodges ranging from 91 to 07 never a turbo problem and some are going over 1,000,000 now on oem turbo

 

You never turn off a hot Eng. Waite till it drops down to a normal temp.I like keeping my EGT from going over 1250 . That way my truck will last a lot longer.All you need to do is shift down when need and watch your pyro temp