K & W Fiberlock

I know this product as all head gasket "repair" products will be rejected by the Subaru mechanics and specialists, however I tried it several weeks ago with success.  K & W Fiberlock was at Auto Zone with similar products like Blue Devil, which I tried a couple years ago.  I called the company before buying it, since it said they offered a double money back guarantee, and a nice lady said they are a big company that honors their word.  Since putting it in I have driven a couple thousand miles or so with no overheating or bubbles.  My head gasket problem was probably pretty minor though.  I spoke with Montesi auto in Waterbury and he said that Blue Devil did not work when he followed all the steps, probably most people give up when making the company honor their guarantee, I got my money back with Blue Devil after contacting the state AG on this consumer issue.  

Has anyone tried this product?  What are the risks to the radiator, or other cooling system parts?  

As with many of these products, youtube has a number of comments:

Edited October 18, 201411 yr by ThosL