I installed my 203* t-stat about a month ago, put about 4-5 tanks of fuel in the ole gal since. I drive min 100 miles a day (70 hwy w/ cruise) and i was getting a consistent 19.8-20 mpg, with the new stat that fell to 18.5-18.8. What gives? I thought this thing was suppose to help with mpg. I dont have a ECT gauge other than factory so I dont know more specific numbers, but I swear I think it runs a tad cooler from where it used to be. Is there some stamping on the tstat itself to verify which one i have?

On the bright side, my billet tstat housing does not leak, no permatex needed.

 

Look in my album....I have a pick of a 203* in there. I'm on my phone or I would give a link...sorry

 

Humm, when Jody was live tuning my truck he said that my oil temps were pretty high like on his ex. He told me I should actually switch to a cooler thermostat like a 180 deg. By the way clay do you sell one? I wonder if tour hotter t stat isn't actually making your fan clutch engage more often and causing your loss in fuel milage! It has been dang hot around here lately! I know hotter fuel will be more efficient as it lowers the combustion point and would cause a more thorough burn but the hotter engine may actually be hurting it! Mine during live tuning stayed around 220-230 deg, oil temp that is and that just seems a lil warm. So with a 13 degree cooler t stat my temps may be closer to 210 which would make me alot happier. Good luck and let's meet up soon. Were talking about a gtg by Houston if you want to join!

 

Yeah, we have a 180º t-stat.

 

I run the lower temp t-stat in mine. Oil temps towing stay under 220*. If running in colder temps like in the winter, the 203 t-stat is helpful, but not so much in the summer months.

The fan clutch makes sense though.

 

Isn't it funny how people talk to Clay in a thread, even when he hasn't even posted in that thread yet? It's like we assume he's monitoring every thread here.

Stewart

 

Winter? What winter? This is Louisiana! Remember where the ones having Christmas and going swimming by noon! Not that warm but the coolest we see is 20's and it's close the roads, send home the kids, and pray for a snow flurry! Haha

 

Under normal driving conditions with 100* ambient temps, I am seeing 210* EOT and less with the DS 203* stat. I actually had lost some mpgs when I switched back to a 195* stat a couple of yrs ago and have since regained it when I went back to the 203* a few months ago. Guess my engine is a little hotter than some and it likes it that way.

 

Damon I've got an edge programmer that reads eot and a few other variables if you want to see what's actually going on. With what Roland said I'd like to know where you eot is running. eot engine oil temp

 

Appreciate it. Ill have to hit you up sometime for that, im kinda curious as well.