Cooling System Specifications Jeep Wrangler I

DESCRIPTION

The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the cooling system. An optional factory installed heavy duty cooling package is available on most models. The heavy duty cooling package generally consists of a radiator that has an increased number of cooling fins and 2 rows of cooling tubes instead of one. An auxiliary electric cooling fan is also used on Cherokee, Comanche and Wagoneer models equipped with a 4.0L engine, heavy duty cooling and/or air conditioning.

Engines with a serpentine accessory drive belt have a reverse (counterclockwise) rotating water pump. Water Pump is identified by "REV" stamped on front of water pump body and "R" stamped into the back of water pump impeller. Engines with standard "V" belt, have a forward rotating water pump.

MAINTENANCE SCHEDULE

Engine coolant protection should be checked once a year at the beginning of the winter season. Change engine coolant every 22,500 miles or 22 months. Maintain a 50/50 mixture of coolant and water.

DRAINING

Except 4.0L

1. Remove radiator cap. Drain coolant by loosening radiator draincock on bottom of tank.
2. On 2.5L engine, drain coolant from engine block by removing drain plug on left rear side of cylinder block.
3. On 4.2L engine, remove 2 drain plugs located on left side of cylinder block.
4. On 5.9L engine, remove centrally located plugs on each side of cylinder block.

Scheme 1

Scheme 2

1. On Cherokee and Comanche models, remove front grill to gain access to radiator draincock. (Scheme 1)
2. On Wagoneer model, remove right turn signal light to gain access to radiator draincock. (Scheme 2)
3. On all models, drain coolant by loosening radiator draincock. To drain coolant from engine, remove drain plug and coolant temperature sensor on left side of cylinder block.

CLEANING

A good cleaning compound removes most rust and scale. Follow manufacturer's instructions in the use of cleaner. If considerable rust and scale has to be removed, cooling system should be reverse flushed.

FLUSHING

1. Reverse flushing is an effective means of removing cooling system rust and scale. Ensure heater control valve is closed (heater off). This will prevent coolant flow with scale and other deposits from entering heater core.
2. To flush radiator, connect flushing gun to water outlet of radiator and disconnect water inlet hose. To prevent flooding engine, use a hose connected to radiator inlet. Use air in short bursts to prevent damage to radiator. Continue flushing until water runs clear.
3. To flush engine, remove thermostat and replace housing. Connect flushing gun to water outlet of engine. Flush using short air bursts until water runs clean.
4. Flush heater core as described for radiator. Ensure heater control valve is set to maximum heat position before flushing heater.

REFILLING

1. Tighten radiator draincock and cylinder block drain plugs. Fill cooling system using a 50/50 mixture of water and coolant. Fill radiator to top. Install radiator cap.
2. On all models except Cherokee, Comanche and Wagoneer with 4.0L engine, add sufficient coolant to reserve bottle to raise coolant level to the FULL mark. Operate engine with radiator and reserve bottle caps in place. Turn heater control switch to the HEAT position.
3. On Cherokee, Comanche and Wagoneer models with 4.0L engine, fill coolant to the inside post in pressure bottle. The top of post is FULL mark. Operate engine with radiator and pressure bottle caps in place. Turn heater control switch to the HEAT position.
4. On all models, after engine has reached normal operating temperature, shut engine off and allow to cool. Add coolant to reserve bottle or pressure bottle as required.

Scheme 3

1. Visually inspect thermostat for corrosion and proper sealing of valve and seat. If okay, suspend thermostat and thermometer in a 50/50 mixture of coolant and water. (Scheme 3) Do not allow thermostat or thermometer to touch bottom of container. Heat water until thermostat just begins to open.
2. Read temperature on thermometer. This is initial opening temperature and should be within specification. Continue heating water until thermostat is fully open and note temperature. This is the fully opened temperature. If either reading is not to specification, replace thermostat. See «COOLING SYSTEM SPECIFICATIONS»(/jeep/wrangler/i-1986-1995/remont/cooling-system-mechanical/#cooling-system-specifications) table.

PRESSURE TESTING

Note. A pressure tester is used to check both radiator cap and complete cooling system. Follow tool manufacturers instructions when operating pressure tester.

Radiator Cap

Visually inspect radiator cap, then dip cap into water and connect to tester. Pump tester to bring pressure to upper limit of cap specification. (Scheme 4) See COOLING SYSTEM SPECIFICATIONS table.

Scheme 4

1. With engine off, wipe radiator filler neck seat clean. Fill radiator to correct level. Attach tester to radiator and pump tester until pressure is at upper level of radiator pressure cap rating. See «COOLING SYSTEM SPECIFICATIONS»(/jeep/wrangler/i-1986-1995/remont/cooling-system-mechanical/#cooling-system-specifications) table.
2. If pressure drops, inspect for external leaks. If no leaks are apparent, detach tester and run engine until normal operating temperature is reached. Reattach tester and observe. If pressure builds up immediately, a possible leak exists from a faulty head gasket, crack in cylinder head or engine block. CAUTION: Pressure may build up quickly. Release any excess pressure or cooling system damage may result.
3. If there is no immediate pressure build up, pump tester to within system pressure cap range. Vibration of gauge pointer indicates compression or combustion leak into cooling system. Isolate leak by shorting each spark plug wire. Gauge pointer should stop or decrease vibration when leaking cylinder is shorted. COOLING SYSTEM SPECIFICATIONS Application Thermo. Temp. °F (°C) Rad. Cap psi Coolant Capacity Qts. (L) 2.5L 195 (91) 12-15 (1) 10 (9.5) 4.0L 195 (91) 12-15 12 (11.4) 4.2L 195 (91) 12-15 10.5 (9.9) 5.9L 195 (91) 12-15 15.5 (14.7) (1) Wrangler 9 qts. (8.5L).

See also:
• COOLING SYSTEM SPECIFICATIONS