Chrysler PT Cruiser, Service & Repair Manual, Page: 278 / 2078

(11) Slowly fill coolant reserve/recovery bottle to at
least the FULL HOT mark with the recommended
coolant. It may be necessary to add additional cool-
ant to the reserve/recovery bottle after three or four
warm-up/cool down cycles to maintain coolant level
between the FULL HOT and ADD marks.This is due
to the removal of trapped air from the system.
CLEANING
CAUTION: Internal radiator pressure must not
exceed 138 kPa (20 psi) as damage to radiator may
result.
Reverse flushing of cooling system is the forcing of
water through the cooling system. This is done using
air pressure in the opposite direction of normal cool-
ant flow. It is usually only necessary with very dirty
systems with evidence of partial plugging.
(1) Drain cooling system. Remove thermostat hous-
ing and thermostat. Install thermostat housing.
(2) Connect a suitable cooling system flusher and
follow instructions supplied with flusher.
INSPECTION
After performing a cleaning/flush procedure,
inspect all hoses, clamps and connections for deterio-
ration and leaks. Inspect radiator and heater core for
leaks.
COOLANT
DESCRIPTION
CAUTION: Use of Propylene Glycol based coolants
is not recommended, as they provide less freeze
protection and less corrosion protection. Do not
mix coolant types. If coolant other than Mopar
T
Antifreeze/Coolant, 5 Year/100,000 Mile Formula or
equivalent is added, the mixed coolant will have a
reduced service schedule.
The use of aluminum cylinder heads, and water
pumps requires special corrosion protection. Mopar
t
Antifreeze/Coolant, 5 Year/100,000 Mile Formula or
equivalent ethylene glycol based coolant with corro-
sion inhibitors (called HOAT, for Hybrid Organic
Additive Technology) is recommended. This coolant
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 solu-
tion. Mixing of coolants other than specified (non-
HOAT), will reduce the 5 year/100,000 mile corrosion
protection.
DIAGNOSIS AND TESTING - COOLANT
CONCENTRATION TESTING
Coolant concentration should be checked when any
additional coolant was added to system or after a cool-
ant drain, flush and refill. The coolant mixture offers
optimum engine cooling and protection against corro-
sion when mixed to a freeze point of -37°C (-34°F) to
-46°C (-50°F). The use of a hydrometer or a refracto-
meter can be used to test coolant concentration.
A hydrometer will test the amount of glycol in a
mixture by measuring the specific gravity of the mix-
ture. The higher the concentration of ethylene glycol,
the larger the number of balls that will float, and
higher the freeze protection (up to a maximum of
60% by volume glycol).
A refractometer (Special Tool 8286)(Refer to 7 -
COOLING - SPECIAL TOOLS) will test the amount
of glycol in a coolant mixture by measuring the
amount a beam of light bends as it passes through
the fluid.
Some coolant manufactures use other types of gly-
cols into their coolant formulations. Propylene glycol
is the most common new coolant. However, propylene
glycol based coolants do not provide the same freez-
ing protection and corrosion protection and is not rec-
ommended.
CAUTION: Do not mix types of coolant—corrosion
protection will be severely reduced.
Fig. 7 Filling the Cooling System
1 - SPECIAL TOOL 8195 FILLING AID FUNNEL
2 - PINCH OVERFLOW HOSE
7 - 42 ENGINE - 2.0/2.4L DOHC
PT
ENGINE - 2.0/2.4L DOHC (Continued)