acteristics than ethylene glycol. This can increase
cylinder head temperatures under certain conditions.
Propylene-glycol/Ethylene-glycol Mixtures—Should Not Be
Used in Chrysler Vehicles
Propylene-glycol/ethylene-glycol Mixtures can
cause the destabilization of various corrosion inhibi-
tors, causing damage to the various cooling system
components. Also, once ethylene-glycol and propy-
lene-glycol based coolants are mixed in the vehicle,
conventional methods of determining freeze point will
not be accurate. Both the refractive index and spe-
cific gravity differ between ethylene glycol and propy-
lene glycol.
CAUTION: Richer antifreeze mixtures cannot be
measured with normal field equipment and can
cause problems associated with 100 percent ethyl-
ene-glycol.
DIAGNOSIS AND TESTING - COOLING SYSTEM
LEAKS
ULTRAVIOLET LIGHT METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys-
tem. The additive is highly visible under ultraviolet
light (black light). Pour one ounce of additive into
cooling system. Place heater control unit in HEAT
position. Start and operate engine until radiator
upper hose is warm to touch. Aim the commercially
available black light tool at components to be
checked. If leaks are present, black light will cause
additive to glow a bright green color.
The black light can be used in conjunction with a
pressure tester to determine if any external leaks
exist (Fig. 1).
PRESSURE TESTER METHOD
The engine should be at normal operating temper-
ature. Recheck the system cold if cause of coolant
loss is not located during the warm engine examina-
tion.
WARNING: HOT, PRESSURIZED COOLANT CAN
CAUSE INJURY BY SCALDING.
Carefully remove coolant recovery pressure con-
tainer cap and check coolant level. Push down on cap
to disengage it from stop tabs. Wipe inside of con-
tainer and examine lower inside sealing seat for
nicks, cracks, paint, dirt and solder residue. Inspect
radiator-to- pressure container hose for internal
obstructions. Insert a wire through the hose to be
sure it is not obstructed.
Inspect cams on outside of pressure container. If
cams are damaged, seating of pressure cap valve and
tester seal will be affected.
Attach pressure tester (7700 or an equivalent) to
coolant pressure container (Fig. 2).
Fig. 1 Leak Detection Using Black Light - Typical
1 - TYPICAL BLACK LIGHT TOOL
Fig. 2 PRESSURE TESTING
1 - PRESSURE RESERVOIR CAP
2 - PRESSURE RESERVOIR
3 - PRESSURE TESTER
7 - 10 ENGINE VA
COOLANT (Continued)
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