We had the same issue with overheating really badly and with advice from Savannah Buzz found the real issue, a block radiator. I replaced the rad and surprise the engine temps dropped easily 20 or more degrees and remain steady with little change between driving and idle. I tore open the old rad and found it was 50% block with what look like leak seal crap and old chunky coolant. It cost not very much out of England and was the best thing we have done to the truck.

 

When I first installed the 180 thermostat in mine the engine tick went away, but it has since come back.

 

Same exact issue for me, replaced radiator and put in genuine 180 tstat. Driving temps around 186-188, idle usually 195-198 tops out at 202 if sitting for a long time. My radiator was plugged up as well. Bonus that my tick has never returned since.

 

While your temps are definitely in the more acceptable range, I would not consider them "normal" for that stat. Did you have a hunch you were running warm to begin with, thus the scangauge ??? Hell, if you got all the freaking air out the first time after dumping coolant whilst changing stat, you did good. Myself, I wouldn't be satisfied, cause I know it should be running cooler. But, that is just me.

 

I installed a Motorad in my '04 a few months back and I'm now getting a steady 194-199 in all conditions - idling, highway, whatever. I'm happy with the lower temps but I'm most happy with the narrow range I now operate in. Before the change I was seeing 25 degree temp swings between idling and highway.

 

It didn't seem to be running hot before I got the scangauge, I just like having them on all my cars since the analogue gauges are pretty much worthless and by the time they move you're usually moments from catastrophic failure. I'll probably run this setup for a while and see if things normalize once the Water Wetter gets pulled into the coolant loop, I think right now it's still almost all sitting in the fill tank.

Eventually I'll replace the radiator, but since I just ordered a CDL kit and some other goodies the bank account has to recover first. Is the Nissen radiator that everyone seems to use a direct replacement with stock or is it an upgrade performance wise?

 

direct replacement.