The "NOSE-TEST" will tell you the plain truth about ANTI-FREEZE

From the standpoint of evaporation there are two kinds of anti-freeze—the kind that boils away and the kind that does not boil away. There is no middle ground. Some boil-away antifreezes, however, have been "treated" to "decrease evaporation," and many car owners may get the impression that such products are all-Winter, one-shot, non-evaporating anti-freeze. Such an impression would be wrong. For such anti-freezes boil off rapidly when the engine is operating at high speed. An easy way to make sure that you get an all-Winter, one-shot product is by the lack of odor. Eveready Prestone is absolutely odorless—all boil-away anti-freezes, on the other hand, have a noticeable odor.