Is the 180 temp. stat out yet for the 04 Hemi?

 

I haven't checked, but I wouldn't swap it without being able to reprogram the computer. I put a 180 on my Chev 454 motorhome thinking I was doing it a favor by running cooler. Problem is, the computer is set to run at 195, so at the 180 it thinks it's still warming up and runs it richer and never goes into closed loop. I ended up fouling an o2 sensor and flunking emissions testing.

I've got to assume the Hemi emissions system is similar.

 

I'd stay away from a low temp stat on the newer vehicles because of the mentioned computer confusion. Also, why switch to a cooler thermostat? I don't think that 15* will make a huge difference in power, if that is the reasoning. If it is because you tow a bunch, the stock system works really well and unless there is a lurking problem, you shouldn't have any overheating issues.

 

with the Jeeps we stay away from the lower temp stats as well...when you run in open loop and dumps the fuel in, not only will is it common to foul the O2 sensors, but over time you begin dilluting the oil with fuel and will cause premature wear.