Both the 4.0L and 4.7L engines use 195� thermostats for all model years
from 1999-2004. When replacing a thermostat it is very important to
install one with the same temperature rating (the only exception might
be with certain performance modifications or chips that recommend or
require a different temperature thermostat).
4.0L engine - Draining the cooling system WARNING: DO NOT REMOVE THE
CYLINDER BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR DRAINCOCK WITH SYSTEM
HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.
1. DO NOT
remove radiator cap first. With engine cold, locate radiator draincock
on the right lower side of radiator facing to rear of vehicle.
Attach one end of a hose to the draincock. Put the other end into a
clean container. Open draincock and drain coolant from radiator. This
will empty the coolant reserve/overflow tank. The coolant does not have
to be removed from the tank unless the system is being refilled with a
fresh mixture. When tank is empty, remove radiator cap and continue
draining cooling system. To drain the engine block of coolant, remove
the cylinder block drain plug, located on the side of cylinder block
below the exhaust manifold.
4.0L engine - refilling the cooling system Coolant recommendations and
cautions: The recommended mixture is 50/50 ethylene-glycol and low
mineral content water. Never use pure antifreeze. Only Mopar Antifreeze
Coolant, 5 Year/100,000 Mile Formula (glycol base coolant with
corrosion inhibitors called HOAT) is recommended. This coolant offers
the best engine cooling without corrosion when mixed with 50% distilled
water. Antifreeze mixture must always be at least 44%, all climates
year round. Maximum protection (-90d) is provided with a 68% mixture
protection. If the percentage is lower than 44 percent, engine parts
may be eroded by cavitation, and cooling system components may be
severely damaged by corrosion. CAUTION: Mopar 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 protection.
CAUTION: Do not use coolant additives that are claimed to improve
engine cooling. 4.0L coolant capacity: 1999-2000: 13.0 qts. (including
2.3 qts. for resevoir) 2001-2004: 15.0 qts. (including 1 qt. for
1. Tighten the radiator draincock and the cylinder block drain plug(s)
2. Fill system using a 50/50 mixture of ethyleneglycol
antifreeze and low mineral content water. Fill radiator to top and
install radiator cap. Add sufficient coolant to the reserve/overflow
tank to raise level to FULL mark.
3. With heater control unit in the
HEAT position, operate engine with radiator cap in place.
engine has reached normal operating temperature, shut engine off and
allow it to cool. When engine is cooling down, coolant will be drawn
into the radiator from the reserve/overflow tank.
5. Add coolant to
reserve/overflow tank as necessary. Only add coolant to the
reserve/overflow tank when the engine is cold. Coolant level in a warm
engine will be higher due to thermal expansion. To purge the cooling
system of all air, this heat up/cool down cycle (adding coolant to cold
engine) must be performed three times. Add necessary coolant to raise
tank level to the FULL mark after each cool down period.
For more details, you can refer to the Jeep WJ Service Manual Section-07-Cooling-System-Ewj7