doesn't specifically say.
Here is an interesting tidbit though.
"EC-1 is Caterpillar's industry specification for an extended service, or long life,
coolant. EC-1 defines the minimum requirements of a long life engine coolant and coolant
extender intended for use in Caterpillar engines. EC-1 defines the physical and chemical
properties, compatibility characteristics, bench and performance testing, and field testing
A coolant meeting EC-1 also meets ASTM D4985. What makes EC-1 unique from other
coolant specifications, is the field-testing. Field-testing establishes the practice for
evaluating the ability of a long life coolant to provide acceptable corrosion control and
cooling system performance with significantly reduced or no maintenance additions of
inhibitor in field service.
To summarize the field testing method; There must be a minimum of six engines of known
initial condition, monitored for coolant and cooling system condition, subject to full tear
down inspection upon completion of the test. Additionally, there must be at least one
copper-brass radiator and one aluminum radiator included in the test. Preferred application
is line-haul-trucking service, but any vehicle application operating at greater than 60% load
factor is considered acceptable. Engine component inspection and coolant sample analysis
results determine acceptable performance.
Caterpillar Extended Life Coolant was introduced once the stringent requirements of EC-1
were met. EC-1 ensures that the coolant not only performs in the laboratory, but more
importantly, on the road and at the job site where it counts most to the customer."