To recap: One aquaeous accumulator with two sources of water touching any of its faces (except below) can keep a combustion engine full of water up to the stable temperature which is 4900,6 °C. An engine will heat up to this point and stay there unless it store more than 6k MJs of energy. After an engine stores up more it will start to heat up again and no amount of water will keep it cooled. A redstone energy cell powered directly by a combustion engine cannot take in all of the energy the engine produces which will proceed to overload, overheat and explode. Redstone energy conduits are able however to even out these bursts of power over several ticks, this means that a redstone energy cell can store all of the energy produced without loss. In case the redstone energy cell is full, all the extra energy is dissipated, with no harmful effects, and the engines won't build up any power, this extra power is wasted however.
