Operator`s manual

Cooling System 43
Additives
Additives are part of most antifreeze and
should be tested for and added to all
coolant mixtures using normal antifreeze. If
extended life coolant is used, the additives
are in the product when mixed. Both types
need to have additives added to after a time.
Additives help prevent rust, scale and
mineral deposits from forming. Additives
also protect metals from corrosion, prevent
water pump and cylinder liner cavitation
and contain anti-foaming agents. Additives
are depleted during normal engine operation
and need to be replaced. For normal
coolant mixture, this means the addition
of Supplemental Coolant Additives (SCA)
at any time the additive goes below the
recommended level. For extended life
coolant mixture, this means an extender
package added halfway through the coolant
lifetime.
Nitrites or nitrite and molybdate additives
protect the cylinder liner from cavitation
erosion. Nitrites deplete over time, creating
the need for SCAs or extender. Other coolant
additives also deplete and need replacement.
A too low concentration of additives in
the coolant will not provide the protection
required by the cooling system. A too high
concentration of additives in the coolant can
cause additives to solidify and drop out of
the solution, depositing inside the cooling
system or form a gel in the radiator. Deposits
can be in the form of sludge and scale.
Deposits accumulate on hot engine surfaces,
reducing the effectiveness of the cooling
system or causing water pump leaks.