03black wrote:
Question: I am in the process of finishing up the building of a DIY serviceable thermostat (found plans over on the other KJ site and contacted the author for cleaned up plan versions). Is it better to put in a 192 degree Hemi thermostat or go with a 205 degree Hemi thermostat?
I live here in the desert in SoCal with summer temps around 95 to 105 and with winter temps in the 40 to 60. Also, have the heavy duty cooling clutch and 11 blade fan mechanical fan install for the local trail runs. I have not overheated with this setup and the factory thermostat but I also wanted to improve the reliability of this engine and make improvements where I can.
Thoughts?
What opening temperature thermostat you should use depends upon several factors and assumes that you have a fully functioning cooling system.
1) ... your driving conditions.
2) ... the kind of "do it yourself" thermostat assembly you are creating.
If your DIY thermostat is one based on a plan to re-use the cheap cast aluminum O.E. thermostat housing, I can tell you that the chamber the HEMI thermostat valve rests in is not properly sized for this massive valve and there may be coolant flow issues. I discovered this years ago when I first set out to create a serviceable thermostat assembly for the Liberty CRD engine. That is why I created an entirely new housing with a properly sized chambers; exactly the same size as the one in the HEMI engine water pump housing.
If there are coolant flow issues you may have a problem with rising engine temperatures in high demand situations. I therefore would be cautious and run the 192 degree valve as a hedge against overheat events.