kstopp

I have been noticing on long highway drives especially with lots of down-hill portions that my temperature gauge will drop down significantly. It will go down to 70-80*C (167*F-176*F). Usually on the straight stretches or up-hill I will see 90-95*C (194*F-203*F). Never sits straight up at the 100*C (212*F) mark or past unless I sit in traffic for a while, it will slowly reach that mark. I'm getting a pretty big MPG loss because of this I think.

Almost every part of my cooling system is new:

New OEM-style replacement rad (Parts store)
New Stant Superstat 195*F thermostat
New Stant rad cap
New Bosch water pump
New clutch fan
New rad hoses and heater hoses
Bypassed coolant diverter valve
Flushed out forward and reverse block and heater core

I'm thinking that the Stant thermostat is letting me down here, would I be better off with an OEM Mopar 195* or should I step up to an aftermarket 205* stat?

Another solution might be to run a cold weather blanket? But I don't think I see low enough temps to warrant that. Usually the coldest I see is about -10*C (14*F).

playbass

Yup, this happened to me last winter and it was because my tstat was not closing properly. I was using a Stant 195* stat back then, and when I swapped in a Mopar, the temp stayed firm all winter.

DFlintstone

Same here. I used a non OEM T-stat, (from Napa). Worked but due to not being perfectly aligned it didn't quite seat. While swapping the 195* Mopar I looked at the other (new) one and bent it a little so it does seat. Saved it under the seat....

Be sure to put the hole UP at 12:00 if it has one. (air bleed)