Thermostat 871

[the missing link]

I know , I know one more dumb ? But hey I got to be good at something ...
I have to do my thermostat on my 871 parking lot style .
My ? Is is there anything I should look for or check . I know I should know all this but like I said I am real good at asking real dumb ?
Thank you for all your time and info


P.s it is not " closing " all the way letting the truck cool off to , well I had at 155 for a brief min (m/t) going down a big hill . It usually won't cool down that much . It just started about 70 Kms ago and I am loaded 80% of the way back so it should be good back to town ....

Thanks again ....

Oh one more ? What do you think about the waterpump ... Lifespan . I am thinking of changing it out this spring good , bad ,or not necessary ( 980,000 ) Kms and way ,way too many hrs 15,000 ....
Just don't want problems when it's time to go to work or in the bush ....
Thanks again ,again ....