hi all. i am trying to formulate some testing of different motor oils. i am looking to document which oils have better cooling properties. i read some info years back that a straight oil like SAE30 actually cools better than say a 5w30, reason being is because the multi-grade uses long chained polymers which uncoil as they get hotter which affects the cooling abilty of the oil. but before i design my test apparatus i want to get clarity on what makes for a better cooling fluid. the specific heat is one property of a substance, but that alone to me does not define a better cooling fluid. is there a property of fluids that define endothermic and exothermic rates? in other words, if a fluid flows over a metal channel which property of fluids defines which fluid absorbs the most energy given a fixed flow rate of the fluid? i am thinking my apparatus will be something like this. a rectangular box, ~12" on the long side, ~4" on the short side, and about ~6" tall to hold fluid around 4"-5" high. this "box" is made of 1" thick rigid foam board with a 1/4thick aluminum plate siliconed to one end of the box. on the opposite end will be an immersion heater. i will measure external temp of the aluminum vs time. i am figuring the better cooling fluid will be the one which shows the rate of temp change to be the fastest regardless of what the equilibrium temp is. does this make sense?