If you need to seal minor coolant leaks, cracks in blocks, heads and radiators without expensive repairs, look no further than Rislone Block Seal Stop Leak with Liquid Copper. Rislone Block Seal contains liquid copper that is ideal for larger cracks and leaks that conventional stop leaks cant fix. Leaks are stopped by organic and synthetic fibres catching onto any holes or cracks, the fibres then build up and the added copper particles all bond together creating a composite plug. Finally, liquid sodium silicates (glass) catalyse and harden the composite plug at the vehicles operating temperature, creating a permanent repair. The easy to use 1 step formula is safe to mix with all coolant types and colours and is even suitable to use with straight water; saving you the hassle of flushing the cooling system before use. Whilst this product is designed to repair minor issues, it may not be a suitable repair method for moderate or large issues, and may cause further problems in some circumstances. Before use, if you are unsure please check with your mechanic to ensure that this product provides a suitable repair for your issue. Dosage: Use 1/2 (half) bottle in a small cooling system, such as 4 cylinders with no A/C. Use 1 (one) bottle for regular size systems, which are for most 4, 6, 8 and 10 cylinder engines.