[TKR]

Hello strenge and welcome to the forum from N.E. Indiana!!! I'm just asking, but did you check your antifreeze level? Low level could cause the problem your having, or like you said the thermostat! Good luck!!

 

[TKR]

You have to drain coolant low enough so you can remove the upper hose. It has a clip at each end of the hose that you have to slide to get the hose removed. Then there are I believe 3 bolts to remove to get the thermostat housing off. It is a dual thermostat. Go to you tube and watch the video from PowerStroke Tech Talk w/ARod. You'll see what I'm talking about.