Review on 🔧 K&W 401224 FiberLock Head Gasket & Block Repair - 32 Fl Oz: Reliable Solution for Engine Head Gasket and Block Issues by Ronnie Cole

Great product. Does not require draining of existing coolant. You must follow the instructions on the back of the bottle. Do not watch YouTube videos or you will add too much or maybe too little. For those who want to know. The main ingredient is sodium silicate, also known as "water glass". Dries/cures on contact with heat and air. My 2005 Chevy Tahoe was leaking coolant from either a bad head gasket or a cracked head with no outward signs of a coolant leak. I wanted to try this without removing my head. I followed the directions on the back of the bottle and added half to the top radiator hose. Visually, it leaves little shiny flakes of copper or aluminum in your coolant, which along with the invisible Kevlar are part of the additive package. Update: 07/30/2018. Used a truck towing service for two summers. No loss of coolant from the expansion tank. At the same level, maybe one day I'll change the cylinder head gasket. This product did exactly what I wanted. Good product! Thanks CRC