HOAT COOLANT
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.
CAUTION: Use of Propylene-Glycol based coolants is not recommended, as they provide less freeze pro-
tection and less corrosion protection.
The cooling system is designed around the coolant. The coolant must accept heat from engine metal, in the cylinder
head area near the exhaust valves and engine block. Then coolant carries the heat to the radiator where the tube/
fin radiator can transfer the heat to the air.
The use of aluminum cylinder blocks, cylinder heads, and water pumps requires special corrosion protection.
Mopar
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Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769), or the equivalent ethylene-glycol base coolant
with organic corrosion inhibitors (called HOAT, for Hybrid Organic Additive Technology) is recommended. This cool-
ant offers the best engine cooling without corrosion when mixed with 50% ethylene-glycol and 50% distilled water to
obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh
properly mixed coolant solution.
CAUTION: Mopar
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Antifreeze/Coolant, 5 Year/100,000 Mile Formula (MS-9769) may not be mixed with any
other type of antifreeze. Mixing of coolants other than specified (non-HOAT or other HOAT), may result in
engine damage that may not be covered under the new vehicle warranty, and decreased corrosion protec-
tion.
COOLANT PERFORMANCE
The required ethylene-glycol (antifreeze) and water mixture depends upon climate and vehicle operating conditions.
The coolant performance of various mixtures follows:
Pure Water- Water can absorb more heat than a mixture of water and ethylene-glycol. This is for purpose of heat
transfer only. Water also freezes at a higher temperature and allows corrosion.
100 percent Ethylene-Glycol - The corrosion inhibiting additives in ethylene-glycol need the presence of water to
dissolve. Without water, additives form deposits in system. These act as insulation causing temperature 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).
50/50 Ethylene-Glycol and Water - Is the recommended mixture, it provides protection against freezing to -37°C
(-34°F). The antifreeze concentration must always be a minimum of 44 percent, year-round in all climates. If per-
centage is lower, engine parts may be eroded by cavitation. Maximum protection against freezing is provided with a
68 percent 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
specific heat of antifreeze is lower than that of water.
CAUTION: Richer antifreeze mixtures cannot be measured with normal field equipment and can cause prob-
lems associated with 100 percent ethylene-glycol.
COOLANT SELECTION AND ADDITIVES
The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. Only
Mopar
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Antifreeze/Coolant, 5 Year/100,000 Mile Formula (glycol base coolant with corrosion inhibitors called HOAT,
for Hybrid Organic Additive Technology) is recommended. This coolant offers the best engine cooling without cor-
rosion when mixed with 50% distilled water to obtain to obtain a freeze point of -37°C (-35°F). If it loses color or
becomes contaminated, drain, flush, and replace with fresh properly mixed coolant solution.
PM
ENGINE
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