About 7 or 8 years ago I was having a heating problem. Someone suggested an additive available on Amazon that would lower the temp about 10-12 degrees . It could be added to antifreeze and was a non automotive product. It was a clear liquid in a pint bottle .I had a new radiator in the box but decided to try this first and it has worked great for the past 6 or 7 years. The new radiator is still in the box. what is this stuff? The bottle it came in says "lamp oil"