So far I've checked with 3 Toyota dealerships. They sell the same gallon of 50/50 pre-diluted Toyota Super Long Life coolant for $18, $25, and $30--quite a wide swing in pricing from $18 to $30. Do you think the Toyota dealership that's only charging $18 is selling very old stock? Could something be wrong with their low-priced coolant? What gives with the wide variation?