Right, first hand experience. We sell Kseal at work and when my 318 was loosing coolant, i thought why not give it a go. This stuff has copper and ceramic in it. When it sets, it literally sets as hard as glass. The water outlet on the back of the head seemed to be the cause of my troubles. So i decided to replace the plastic pipe. The old plastic had fractured with age, and the Kseal had fused the broken plastic to the inside of the head casting. The was no way to removed it with out taking the head off. I had to cut down the new pipe and make a paper gasket and seal it with gasket cement. Nightmare job. If yours is the M43 engine, I would suspect the head gasket. I chased a coolant fault around on mine for many months, no CO in the coolant, no oil or cream cheese anywhere. Eventually after replacing most of the plumbing, the new parts held the water long enough for the culprit to finally be found, the head had corroded on number four, just enough to allow the gsket to finally fail. Propably not what you want to hear, but I would definatley start to consider head gasket. Especially if your hoses are getting hard at normal temps. Having said all the above, we've had guys buy the stuff to go in K series Rover's and it has fixed those head gaskets, and that's a dog of an engine IMO. Basically, check out all other stuff before you try it. I'll keep all crossed that i'm wrong. John.