Now that the unit has cooled off and "normal" have you had an oppertunity to try and turn the engine over, ? using the 'dead crank' feature, or worse by hand [grasping the fan blade] or somehow accessing the flywheel and 'barring it over' my caution would be to be darn sure the battery power was not availible under any of these efforts beyond the dead crank effort. I get your sense or thought that it only took one jug of coolant, but worse it only holds 2 jugs, so it might well have seized up, but you will be first to know or discover this. And above all, I so get the impatience you talk about not having, when I reflect back on things or situations I have caused damage too, my lack of impatience is nearly always at the root of it. good luk mac/mc