I drove into town...maybe 5-6 miles to get some fuel... Left truck running for about 6-7 mins while i put some in and paid...Head back home and happen to look down after about 3 miles of driving and see my temp gauge was up to where it would run during the summer(notch or so under 210). It was 23f, and most of this winter its been running around 175(4-5 notch over 160)...
Anyways i came to a speed zone dropped to 40 for about a mile. Watched the gauge drop slowy down to the 175 mark agin....Hmmm Speed back up to 60 again and gauge goes right up w/it....Not as high tho, then came down again to 175 for about the last 1.5 miles to home...

It was windy today, but Ive never noticed anything like this before.Is it possible that it wasnt getting airflow or something in there??
Also, Im not running the winter cover. I looked real quick in the front, but didnt see anything blocking it...
Just kinda curious....
Note-See Sig truck is stock, besides tires and gm bugvisor...no powerboxs or anything...

Well, diesels are real engine load dependent when it comes to heat generation.

I run with the winter cover on and I will see the thermostat cycle no problem. Plus, during idling periods, the temp will roll off some.

No load on the truck, just me cruising... When out tongiht to go to snomobile club meeting and i saw it do it again...., It was then that it hit me that it was prolly just the thermostat opening....egg on my face, but still cant believe i hadnt seen it in the past....

So is safe to assume that all it is/was is the thermostat building heat, and then opening up??