Cool Runnings!

Hi everyone,kinda new here,got back into the fold at long last with a 96 300tdi auto,a week later,one oil and filter change,one loud bang,lots of white smoke and she'd let go of her turbo,second hand turbo fitted(grazed wrists and knuckles as I didnt remove manifold) all is good,but by god is she running cool now!
My question is,are these generally cool running engines as it is,or has the more than over due service she's had had some impact on this?

Wheres your temp guage it?

Most wont go past half way. Even with the fan missing.

They do take some warming up if stationary.

Oh she only lifts to just over the bottom of the guage,but to be honest,I aint done any great mileage since I changed the turbo,guess I need to have a run really....oh one other thing,when she's reved,the coolant rushes back into the header tank,very visably,but everything else seems ok!