I had seen all sorts of horror stories on the internet about ‘blocked oilways’ and ‘snake oil’ for similar products. I was motivated to buy this product because I had had excellent results with your K Seal. I had a minor break to the head gasket of my 300Tdi Defender, consequently skimmed and repaired, but despite pressure testing I experienced occasional symptoms of the original problem. The independent Land Rover garage determined that there was a tiny fault in the head, they used K-Seal and it has been problem free ever since. Adrian.