Thanks!
With regards to spraying your resistors with coolant, I have recently been measuring resistor values versus temperature. Not having any means to control temperature I have been logging values over the coarse of a day's temperature variation and have found that as the temp increases so to does the resistance but there is a massive lag as temperature drops.
I then applied heat from a heat gun expecting to see resistance climb dramatically but saw it drop substantially, almost as though it went from PTC to NTC. I haven't investigated further but one idea I had is that extreme temperature gradients may be causing thermoelectric voltages throwing readings off