Since there is only the cap on the reservoir, there is a small (1/4") line that goes from the top of the reservoir to the radiator hose inlet on the opposite side of the engine. This is a self bleeding system, but if that line gets clogged up, you cannot bleed the system. Make sure it is clear end to end.
BTW, Dexcool was formulated to reduce erosion on the impeller blades of the water pump. If someone has used another type of antifreeze that contained borates and silicates, then erosion could be a problem. Modern long life antifreezes have eliminated those compounds so it is no longer necessary to use Dexcool, you can use any universal long life antifreeze, but I’d recommend sticking to a major brand though.