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RG74DXH Operator · Service · Maintenance Manual
Specifications
COOLANT SPECIFICATIONS
Coolant / Antifreeze Recommendations for GM Powered Machines
ACDelco DEX-COOL® ANTIFREEZE/COOLANT is a universal engine coolant, which incorporates a patented carboxylate
inhibitor technology. This coolant meets both ASTM D 3306 for automotive service and ASTM D 4985 for heavy-duty diesel
service. It is a nitrite-, nitrate-, phosphate-, silicate-, borate and amine-free formulation which uses a patented carboxylate
technology to provide maximum protection of the six basic metal alloys found in
most heat transfer systems. Since the coolant contains no phosphates or silicates, hard water deposits in the cooling system
are almost eliminated. The low level of abrasive dissolved solids in ACDelco DEX-COOL® ANTIFREEZE/COOLANT
results in improved water pump seal life.1
Your GM powered machine is filled at the factory with GM approved coolant under the GM6277M specification. Rayco
does not warrant use [or mixing] of any other glycol-based coolant in your GM engine. DEX-COOL® is orange in color to
distinguish it from other coolants. Due to inconsistencies in the mixing of the dyes used with DEX-COOL®, some batches
may appear pink after time. The color shift from orange to pink does not affect the integrity of coolant and still maintains the
recommended use-life of the coolant2.
The coolant specification addresses the following concerns:2
• Provides effective, long term corrosion protection for aluminum, brass, cast iron, steel, solder and copper.
• Protects against winter freeze up and minimizes the chance of summer boil over
• Compatible with water pump seal materials and minimizes the formation of abrasive dissolved solids.
• Storage stable for at least eight years.
• 100% biodegradable in its pure unused form.
• Excellent heat transfer properties.
• Nitrite, borate, phosphate, nitrate, and amine free.
• Outstanding hot surface aluminum protection
• Superior protection in high operating temperatures
We recommend the following coolant type for your machine:
• Pre-mixed Extended Life Coolant which meets the GM6277M specification....34°F @ 50% mix / -62°F @ 60% mix
• Diluted [distilled water] Extended Life Coolant which meets the GM6277M specification....-34°F @ 50% mix / -62°F
@ 60% mix
Coolant Maintenance:
• Maintain freeze point between -15°F and -62°F. A 50% mixture has a freeze point of -34°F (refer to freeze point above).
• Use commercially available test strip to test coolant performance at least twice a year .
• Top up low coolant systems with a 50% mixture as required.
• Follow the engine OEM procedures when doing a complete change-out.
Make Proper Antifreeze Additions
Adding pure antifreeze as a makeup solution for cooling system top-up is an unacceptable practice. It increases the
concentration of antifreeze in the cooling system which increases the concentration of dissolved solids and undissolved
chemical inhibitors in the cooling system. Add antifreeze mixed with water to the same freeze protection as your cooling system.
Use the chart below to assist in determining the concentration of antifreeze to use.
NOTICE: The use of additives or Replenishing Supplement Coolant Additives (SCA'S) is not recommended in
conjunction with DEX-COOL® Coolant.
DEX-COOL
Coolant (equiv) Protection Temperature (w/ 15 psi cap)
®
Boiling Protection to -129.4°C (265°F)
Freeze Protection to -24.4°C (-12°F)
Freeze Protection to -36.7°C (-34°F)
Freeze Protection to -52.2°C (-62°F)
36
Concentration
50% antifreeze and 50% water
40% antifreeze and 60% water
50% antifreeze and 50% water
60% antifreeze and 40% water
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