
114 LIGHT AND HEAVY VEHICLE TECHNOLOGY
Testing antifreeze solutions
Since the degree to which an antifreeze solution can
furnish protection depends upon the mixing ratio of
ethylene glycol to water, a hydrometer test is necessary
to indicate whether ethylene glycol or water, or both,
should be added in the event of the radiator requiring
topping up.
A hydrometer is an instrument for determining the
relative density of a liquid, or the number of times a
volume of that liquid is as heavy as an equal volume of
water. It will, no doubt, be more familiar as a con-
venient method for testing the state of charge of a car
battery. In a similar manner ...