2017 f150 3.5l. Looks like some kind of leak stop was added to cooling system. Replacing radiator,water pump, thermostat. How can I flush the motor to get it out of it now that it’s all apart. Thanks

 

Motor seems pretty clean when I flushed it with water. Removed all hoses and there are plenty of them, it is hard to get whatever this stuff is out. Still have to clean oil cooler and steering cooler and heater core.