Operation and maintenance manual

Coolant Recommendations and Specifications QSB4.5 and QSB6.7
Page V-14 Section V - Maintenance Specifications
Fully formulated antifreeze must be mixed with good-
quality water at a 50/50 ratio (40- to 60-percent working
range). A 50/50 mixture of antifreeze and water gives a
-36°C [-33°F] freezing point and a 108°C [226°F] boiling
point, which is adequate for locations in North America.
The actual lowest freezing point of ethylene glycol
antifreeze is at 68 percent. Using higher concentrations of
antifreeze will raise the freezing point of the solution and
increase the possibility of a silica gel problem.
Legend
1 Freezing Point Temperature Scale
2 Boiling Point Temperature Scale
A refractometer must be used to measure the freezing
point of the coolant accurately. Use Fleetguard®
refractometer, Part Number C2800.
Do not use a floating ball hydrometer. The use of floating
ball hydrometers can give an incorrect reading.
Cooling System Sealing Additives
Do not use sealing additives in the cooling system. The
use of sealing additives will:
• Buildup in coolant low-flow areas
• Plug the radiator and oil cooler
• Possibly damage the water pump seal.