WARNING: Antifreeze is an ethylene glycol base coolant and is harmful if swallowed or inhaled. If swal-
lowed, drink two glasses of water and induce vomiting. If inhaled, move to fresh air area, seek medical
attention immediately. Do not store in open or unmarked containers. Wash skin and clothing thoroughly
after coming in contact with ethylene glycol. Keep out of reach of children. Dispose of glycol base coolant
properly, contact your dealer or government agency for location of collection center in your area. Do not
open a cooling system when the engine is at operating temperature or hot under pressure, personal injury
can result. Avoid radiator cooling fan when engine compartment related service is performed, personal
injury can result.

ETHYLENE-GLYCOL MIXTURES

CAUTION: Richer antifreeze mixtures cannot be measured with normal field equipment and can cause prob-
lems associated with 100 percent ethylene-glycol.

The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. Only
Mopar

Antifreeze/Coolant, 5 year/100,000 Mile Formula (ethylene-glycol base coolant with corrosion inhibitors

called HOAT, (Hybrid Additive Technology) is recommended. This coolant offers the best engine cooling without cor-
rosion when mixed with 50% distilled water to obtain a freeze point of -37°C (-35°F).

The required ethylene-glycol (antifreeze) and water mixture depends upon the climate and vehicle operating condi-
tions. The antifreeze concentration must always be a minimum of 44 percent, year-round in all climates. If per-
centage is lower than 44 percent, engine parts may be eroded by cavitation, and cooling system
components may be severely damaged by corrosion. Maximum protection against freezing is provided with a
68% antifreeze concentration, which prevents freezing down to -67.7° C (-90° F). A higher percentage will freeze at
a warmer temperature. Also, a higher percentage of antifreeze can cause the engine to overheat because the spe-
cific heat of antifreeze is lower than that of water.

Use of 100 percent ethylene-glycol will cause formation of additive deposits in the system, as the corrosion inhibitive
additives in ethylene-glycol require the presence of water to dissolve. The deposits act as insulation, causing tem-
peratures to rise to as high as 149°C (300°F). This temperature is hot enough to melt plastic and soften solder. The
increased temperature can result in engine detonation. In addition, 100 percent ethylene-glycol freezes at 22°C
(-8°F ).

PROPYLENE-GLYCOL MIXTURES

It’s overall effective temperature range is smaller than that of ethylene-glycol. The freeze point of 50/50 propylene-
glycol and water is -32°C (-26°F). 5°C higher than ethylene-glycol’s freeze point. The boiling point (protection
against summer boil-over) of propylene-glycol is 125°C (257°F ) at 96.5 kPa (14 psi), compared to 128°C (263°F)
for ethylene-glycol. Use of propylene-glycol can result in boil-over or freeze-up on a cooling system designed for
ethylene-glycol. Propylene glycol also has poorer heat transfer characteristics than ethylene glycol. This can
increase cylinder head temperatures under certain conditions.

Propylene-glycol/ethylene-glycol Mixtures can cause the destabilization of various corrosion inhibitors, causing dam-
age to the various cooling system components. Also, once ethylene-glycol and propylene-glycol based coolants are
mixed in the vehicle, conventional methods of determining freeze point will not be accurate. Both the refractive index
and specific gravity differ between ethylene glycol and propylene glycol.

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ENGINE

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