Get the 180f t-stat from lucky8

 

Atlantic British also sell's the black T-stat from britpart, its stamped 78*c which is almost 175*f, I have tried it many years ago (b4 doing inline), that T-stat works very well, if not better than genuine gray, I know some members here also tried it & like it better than gray,,
But you have to tell Atlantic British to send you the black unit or you may get the other low temp they also sell which is cream color & isn't good.

 

I like the Britpart black thermostat. Temps will vary on engine load (AC on/off or in the mountains/hills), and your location. I am normally in the 182-193F max range in the cooler months, and 188-206F in the warmer months with the AC on.

I'm not worried unless I see a spike past 212F. These engines went for years (when people didn't know much about the cooling system & they were under warranty) with 195F thermostats and they normally ran 200-215F to possibly 200-220F and most are still on the road today. Yes I'm sure they had their HG's replaced, hard lines, throttle body heater plates (I say delete that POS personally), but the fact is now with a 180F thermostat, green coolant, and a well maintained cooling system 182-212F is nothing vs what they rolled off the factory doing for years.

 

 

I run 186.5 194.6 normally with peaks to 201 in heavy traffic and lots of red lights

180 Gray thermostat

 

My truck runs 188-195 cruising. Uphill under load, 197-203. Red lights or idling after driving 201-210, usually 204-206. I only see 203-210 in warm weather with the ac on. My whole cooling system is new. OEM 180 stat, OEM hoses, Nissen rad, hd clutch and fan, new water pump, new temp sensors. System is bled. My original motor ran at similar temps with a 180 stat. Anything below 212 is fine. I'm just not sure how some trucks run cooler without an inline stat. They all seem to vary a bit.

 

They vary because there are at least three types of OEM 180 stat on the market. If you have a white or yellowish one it's likely you will see the temps you describe. The grey or black ones seem to be what get people the lower temps.

 

Black (britpart) or grey OEM LR are the exact temps DT described.

 

I run no higher than 197 with the Grey one from Lucky 8 and I also have an entirely new cooling system... My shop installed a white 180 from AB which was only in service for a week or so and I got the temps DT describes... My previous experience with the grey one from L8 led me to switch back to that one, at which time I noticed an across the board 12 degree temp drop. I did however bleed the crap out of my system over the course of a week, by opening the bleed screw and topping off the coolant there when the engine was cold and the truck parked uphill.

 

I have the black britpart low temp. My temps are anywhere from 176 in extreme cold to 187 in traffic on a 95 degree day with the ac on