Blue Devil Blue Devil pour n go Internet!!. I used blue devil poor n go in a toyota corolla as I had a coolant leak in cylinder #2. I waited until the car was cold and poured the blue devil into the radiator and turned the heat on high as instructed by the directions on the back of the bottle. I ran the car as instructed and left the car over night. The car seemed to run ok for a while but still had a leak inot the #2 cylinder. After letting the car warm up to normal operating temperature the heater would put out nothing but cold air. Long story short I ended up pulling the head off of the engine and there was a layer of sodium silicate coating the inside of the head and it had completely clogged the heater core. The radiator had to be replaced due to the flo being reduced to about 30% of what is normal. DO NOT use blue devil in your engine as it will destroy your engine.