I just looked at a copy of my car's owner's manual from the 1970s. By far the largest section was about maintaining all those strange things in the engine bay!
Current car, the largest section of the owner's manual is the touch screen!
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Procrastination, mankind's greatest labour saving device!
50L custom fuel rack 6x20W 100/20mppt 4x26Ah gel 28L super insulated fridge TPMS 3 ARB compressors heatsink fan cooled 4L tank aftercooler Air/water OCD cleaning 4 stage car acoustic insulation.