Sooo, what's the thought about too small of a themosiphon tank, and the engine (listeroid 6/1) ends up boiling the coolant in the upper outlet. Is that too hot, or as long as 190F coolant comes into the inlet, is that OK ? I never got the radiator and fan hooked up over the summer, and now, we've got a fair amount of cloud cover & rain, my 5Kw of PV is only putting out about 93 watts today ! I'd run it longer, but wanted to know what the risks are, running it HOT. My exhaust fitting nipple runs about 340F (EGT) when it's loaded down with 2600w on the alternator (ST5) Voltage & freq are really good, I run 240V to the XW6048 inverter, which sync's and uses the AC to charge the batteries (fancy bi-directional inverter.) running 50-50 coolant @ 1400' elevation, no pressure cap.