i got up on a cold morning, started my 84 6.9. ran it for a few minutes, noticed the gauge went up to 180°. i shut it off and checked the top hose and the top of the radiator. they were cold. the heater hoses were hot.is this a thermostat issue?

 

Most of these thermostats don't start to open until 192 degrees .

 

ok, the stat is rated 192°. i get that. it just seemed weird that it reached 180 as quickly as it did. and it was a very chilly 30° morning. it usually needed around 10 mins to get up there. always seemed to take a while to pop.
i basically have reservations about the 190 stat. the po had a 180 in it ,and it worked just fine.
i replaced the h2o pump and the fan clutch last year.

 

Replace the t-stat with a Motorcraft one if it isn't. Aftermarket ones don't fit right/stick closed/break quickly.

 

it's a motorcraft. put in 3 yrs ago. probly IS sticking...