The guys at Kammer and kammer's machine shop filled my block with Hardblok Filler 2 years ago but earlier this summer i noticed my car was not staying as cool as it should. So i popped the radiator cap and saw "gravel" looking chunks in my radiator...i pulled the rad out, flushed it, and put it back in and thought not much more of it. Then the next week out, same cooling issues after 2 runs....i got home and popped the cap again and sure enough, more chunks. Come to find out, the hardblok was crumbling. I now have the motor apart and my water jackets look like a rock quarry. What is going on and how do i stop it? I CANT, CANT afford to just chuck the block. Any help would be greatly appreciated!