ENGINE COOLING SYSTEM

Transcription

1 06 3 ENGINE GENERAL Radiator Radiator Coolant reservoir Coolant reservoir Thermostat Water pump Thermostat Water pump Engine Cylinder head Cylinder block (Heater line) Oil cooler <PTC Engine Coolant Flows> Engine Cylinder head Cylinder block Heater Heater SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY Oil cooler <FFH Engine Coolant Flows> Cylinder block side Block #5 Oil cooler Heater Heater water pump inlet pipe Water pump Cylinder head side Cylinder head Coolant outlet port (intake #1) Radiator Water pump

2 4 06 Function Description Cylinder head Intake manifold Coolant outlet port 1. Cylinder head coolant outlet port is integrated into intake manifold. (in front of cylinder #1) : Improved shape and gasket material to prevent coolant from leaking From cylinder head From reservoir From heater In OM 600 engine, coolant inflows through the heater line rear section (cylinder #4 and #5) of cylinder head. However, in D27DT engine, coolant inflows from cylinder block through oil cooler (refer to coolant flows layout in previous page). : It prevents cooling efficiency from decreasing due to coolant separation between cylinder #4 and #5. 3. In OM 600 engine, the cooling fan is installed with water pump, however, in case of D27DT engine, it is connected to water pump with an additional pulley.

3 06 5 Radiator This vehicle has a lightweight tube-and-fin aluminum radiator. Be careful not to damage the radiator core when servicing. Water pump The belt-driven centrifugal water pump consists of an impeller, a drive shaft, and a belt pulley. The impeller is supported by a completely sealed bearing. The water pump is serviced as an assembly and, therefore, cannot be disassembled. Coolant reservoir NOTICE Scalding hot coolant and steam could be blown out under pressure, which could cause serious injury. Never remove the coolant reservoir cap when the engine and radiator are hot. The coolant reservoir is a transparent plastic reservoir, similar to the windshield washer reservoir. The coolant reservoir is connected to the radiator by a hose and to the engine cooling system by another hose. As the vehicle is driven, the engine coolant heats and expands. The portion of the engine coolant displaced by this expansion flows from the radiator and the engine into the coolant reservoir. The air trapped in the radiator and the engine is degassed into the coolant reservoir. When the engine stops, the engine coolant cools and contracts. The displaced engine coolant is then drawn back into the radiator and the engine. This keeps the radiator filled with the coolant to the desired level at all times and increases the cooling efficiency. Maintain the coolant level between the MIN and MAX marks on the coolant reservoir when the system is cold. SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY GENERAL

4 6 06 Thermostat A wax pellet-type thermostat controls the flow of the engine coolant through the engine cooling system. The thermostat is mounted in the water pump housing. The thermostat stops the flow of the engine coolant from the engine to the radiator to provide faster warm-up, and to regulate the coolant temperature. The thermostat remains closed while the engine coolant is cold, preventing circulation of the engine coolant through the radiator. At this point, the engine coolant is allowed to circulate only throughout the heater core to warm it quickly and evenly. As the engine warms, the thermostat opens. This allows the engine coolant to flow through the radiator where the heat is dissipated. This opening and closing of the thermostat permits enough engine coolant to enter the radiator to keep the engine within proper engine temperature operating limits. The wax pellet in the thermostat is hermetically sealed in a metal case. The wax element of the thermostat expands when it is heated and contracts when it is cooled. As the vehicle is driven and the engine warms, the engine coolant temperature increases. When the engine coolant reaches a specified temperature, the wax pellet element in the thermostat expands and exerts pressure against the metal case, forcing the valve open. This allows the engine coolant to flow through the engine cooling system and cool the engine. As the wax pellet cools, the contraction allows a spring to close the valve. The thermostat begins to open at 85 and is fully open at 100. The thermostat closes at 85. Thermostat Begins to open Fully open Operating Temperature () Opening Value () 0.1 8

5 06 7 When closed (up to 85) X. from cylinder head Y. to crankcase Z. from radiator When partially opened (85 ~ 100) When fully opened (above 100) If the cooling system is fully filled with, the coolant is automatically bled through ball valve (arrow) in thermostat. SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY GENERAL

6 8 06 Viscous fan clutch The cooling speed increases approx. 1,000 rpm with wind noise when the engine speed is 4,000 to 4,500 rpm and the coolant temperature is 90 to 95. NOTICE Keep hands, tools, and clothing away from the engine cooling fans to help prevent personal injury. This fan is electric and can turn on even when the engine is not running. NOTICE If a fan blade is bent or damaged in any way, no attempt should be made to repair or reuse the damaged part. A bent or damaged fan assembly should always be replaced with a new one to prevent possible injury. 1. Clutch housing 2. Drive disc 3. Flange 4. Seal ring 5. Needle bearing 6. Cooling fan 7. Oil scraper 8. Spring 9. Pin 10. Bi-metal 11. Bracket cover 12. Separator disc 13. Supply port 14. Lever valve 15. Oil chamber 16. Operating chamber The cooling fans are mounted behind the radiator in the engine compartment. The electric cooling fans increase the flow of air across the radiator fins and across the condenser on air conditioner. The fan is 320 in diameter with five blades to aid the airflow through the radiator and the condenser. An electric motor attached to the radiator support drives the fan. 1. A/C Off or Non-AC Model 1) The cooling fan operates at low speed when the coolant temperature reaches 95 and at high speed when the coolant temperature reaches ) The cooling fan is turned from high speed to low speed at 97 and turns off at A/C On 1) The ECU will turn the cooling fan on at high speed when the A/C system is on.

7 06 9 Engine coolant temperature sensor The Engine Coolant Temperature (ECT) sensor uses a temperature to control the signal voltage to the Engine Control Unit (ECU). Coolant Level Check NOTICE Scalding hot coolant and steam could be blown out under pressure, which could cause serious injury. Never remove the coolant reservoir cap when the engine and radiator are hot. Take precautions to prevent antifreeze coming in contact with the skin, eyes or vehicle body. If contact happens, rinse affected areas iediately with plenty of water. 1. Place the vehicle on a level ground and check the coolant level through the coolant reservoir. 2. Add if needed. Change the coolant if necessary. SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY GENERAL

8 10 06 Coolant Temperature Sensor Temp. Resistance <Coolant Temperature Sensor> <Output Characteristics of Coolant Temperature Sensor> Coolant temperature sensor is a NTC resister that sends coolant temperature to ECU. NTC resister has characteristics that if the engine temperature rises, the resistance lowers so the ECU detects lowering signal voltages. If the fuel injected into the engine through injector has more turbulence, then combusts very well. However, if engine temperature is too low, the fuel injected as foggy state forms big compounds causing incomplete combustion. So the sensor detects coolant temperature and changes coolant temperature changes into voltage then sends to ECU to increase the fuel volume during cold start for better starting. And detects engine overheating for fuel volume reduction to protect the engine. ECU functions as below with coolant temperature sensor signals. 1. When engine is cold, controls fuel volume to correct idle speed 2. When engine is overheated, controls electrical fan and A/C compressor to protect the engine 3. Sends information for emission control Temperature NTC 1 Resistance ( Ω ) 2, NTC 2 Resistance ( Ω ) 6,062 1, Signal Auto amp Ground <Coolant Temperature Sensor Circuit>

9 06 11 Trouble Diagnosis Symptom Low coolant level Excessively high coolant temperature Excessively low coolant temperature Cause Leaks in radiator Leaks in coolant reservoir Leaks in heater core Leaks in hose connection Damaged coolant hose Leaks in water pump gasket Leaks in water pump internal seal Leaks in coolant inlet cap Leaks in thermostat housing Improper tightening torque of cylinder head Damaged cylinder head gasket Coolant leaks (too low coolant level) Improper coolant mixture ratio Kinked coolant hose Defective thermostat Defective water pump Defective radiator Defective coolant reservoir and cap Cracks on cylinder head or cylinder block Clogged coolant passages in cylinder head or cylinder block Clogged radiator core Improper operation of cooling fan Faulty temperature sensor or defective harness Stuck thermostat (with open) Improper operation of cooling fan Faulty temperature sensor or defective harness Action Replace radiator Replace coolant reservoir Replace heater Reconnect hose or replace clamp Replace hose Replace gasket Replace water pump Replace water inlet cap gasket Replace thermostat sealing Retighten Replace cylinder head gasket Add coolant Check coolant concentration Repair or replace hose Replace thermostat Replace water pump Replace radiator Replace coolant reservoir or cap Replace cylinder head or cylinder block Clean coolant passages Clean radiator core Replace cooling fan or repair related circuit Replace sensor or repair related circuit Replace thermostat Replace cooling fan or repair related circuit Replace sensor or repair related circuit SENSOR CONTROL FUEL COOLING LUB EXHAUST INTAKE HOUSING ASSY GENERAL

10 12 06 SPECIFICATIONS Description Unit Specification Cooling system Type - Water cooling forced circulation Coolant Capacity 11.3 Thermostat Type - Wax pellet type Initial opening temperature 85 Fully opening temperature 100 Fully closing temperature 83 Stroke min. 8 Cooling fan Blades 5 Diameter 320 (2) Low speed ON temp 91 Low speed OFF temp 88 High speed ON temp 95 High speed OFF temp 92 High speed ON temp. (By A/C pressure) psi 270 Coolant reservoir Pressure valve opening pressure Kg/cm ~ 1.5 Vacuum valve opening pressure Kg/cm Water pump Type - Centrifugal Impeller diameter 72.3 Impeller blades 10 Radiator Type - Down-flow Core width 701 Core height 372 Core thickness 18 Minimum radiation capability Kcal/h 45,000 Coolant temperature sensor Resistance (at 20) Resistance (at 80) KΩ KΩ 3.33 ~ ~ 0.35 Anti-freeze agent Type ALUTEC-P78 Mixture ratio (water and anti-freeze) 50 : 50