INTERNAL LEAKAGE INSPECTION
Remove the engine oil pan drain plug and drain a small amount of engine oil. If coolant is present in the pan, it will drain first because it is heavier than oil. An alternative method is to operate engine for a short period to churn the oil. After this is done, remove the engine dipstick and inspect for water globules. Also inspect the transmission dipstick for water globules and transmission fluid cooler for leakage.
| WARNING | With radiator pressure tester tool installed on radiator, do not allow pressure to exceed 145 kPa (21 psi). Pressure will build up quickly if a combustion leak is present. To release pressure, rock tester from side to side. When removing tester, do not turn tester more than 1/2 turn if system is under pressure. |
Operate the engine without the pressure cap on the radiator until the thermostat opens. Attach a Pressure Tester to the filler neck. If pressure builds up quickly it indicates a combustion leak exists. This is usually the result of a cylinder head gasket leak or crack in engine. Repair as necessary.
If there is not an immediate pressure increase, pump the Pressure Tester. Do this until indicated pressure is within system range of 110 kPa (16 psi). Fluctuation of the gauge pointer indicates compression or combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic converter, do not short out cylinders to isolate compression leak.
If the needle on dial of the pressure tester does not fluctuate, race engine a few times to check for an abnormal amount of coolant or steam. This would be emitting from exhaust pipe. Coolant or steam from exhaust pipe may indicate a faulty cylinder head gasket, cracked engine cylinder block or cylinder head.
COMBUSTION LEAKAGE TEST - WITHOUT PRESSURE TESTER
DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.
| WARNING | Do not remove cylinder block drain plugs or loosen radiator draincock with system hot and under pressure. Serious burns from coolant can occur. |
Drain sufficient coolant to allow thermostat removal. Refer to THERMOSTAT , Removal . Remove accessory drive belt. Refer to BELT, Serpentine , Removal .
Add coolant to radiator to bring level to within 6.3 mm (1/4 in) of the top of the thermostat housing.
| CAUTION | Avoid overheating. Do not operate engine for an excessive period of time. Open draincock immediately after test to eliminate boil over. |
Start engine and accelerate rapidly three times, to approximately 3000 RPM while observing coolant. If internal engine combustion gases are leaking into cooling system, bubbles will appear in coolant. If bubbles do not appear, internal combustion gas leakage is not present.
VISUAL DIAGNOSIS
When diagnosing serpentine accessory drive belts, small cracks that run across the ribbed surface of the belt from rib to rib, are considered normal. These are not a reason to replace the belt. However, cracks running along a rib (not across) are not normal. Any belt with cracks running along a rib must be replaced. Also replace the belt if it has excessive wear, frayed cords or severe glazing.
For further belt diagnosis, refer to ACCESSORY DRIVE BELT DIAGNOSIS CHART .
Scheme 25
| 1 - NORMAL CRACKS BELT OK |
|---|
| 2 - NOT NORMAL CRACKS REPLACE BELT |
Noises generated by the accessory drive belt are most noticeable at idle. Before replacing a belt to resolve a noise condition, inspect all of the accessory drive pulleys for alignment, glazing, or excessive end play.
| CONDITION | POSSIBLE CAUSES | CORRECTION |
|---|---|---|
| RIB CHUNKING (One or more ribs has separated from belt body) | 1. Foreign objects imbedded in pulley grooves. | 1. Remove foreign objects from pulley grooves. Replace belt. |
| 2. Installation damage. | 2. Replace belt. | |
| RIB OR BELT WEAR | 1. Pulley misaligned. | 1. Align pulley(s). |
| 2. Abrasive environment. | 2. Clean pulley(s). Replace belt if necessary. | |
| 3. Rusted pulley(s). | 3. Clean rust from pulley(s). | |
| 4. Sharp or jagged pulley groove tips. | 4. Replace pulley. Inspect belt. | |
| 5. Belt rubber deteriorated. | 5. Replace belt. | |
| BELT SLIPS | 1. Belt slipping because of insufficient tension. | 1. Inspect/Replace tensioner if necessary. |
| 2. Belt or pulley exposed to substance that has reduced friction (belt dressing, oil, ethylene glycol). | 2. Replace belt and clean pulleys. | |
| 3. Driven component bearing failure (seizure). | 3. Replace faulty component or bearing. | |
| 4. Belt glazed or hardened from heat and excessive slippage. | 4. Replace belt. | |
| LONGITUDAL BELT CRACKING | 1. Belt has mistracked from pulley groove. | 1. Replace belt. |
| 2. Pulley groove tip has worn away rubber to tensile member. | 2. Replace belt. | |
| "GROOVE JUMPING" (Belt does not maintain correct position on pulley) | 1. Incorrect belt tension. | 1. Inspect/Replace tensioner if necessary. |
| 2. Pulley(s) not within design tolerance. | 2. Replace pulley(s). | |
| 3. Foreign object(s) in grooves. | 3. Remove foreign objects from grooves. | |
| 4. Pulley misalignment. | 4. Align component. | |
| 5. Belt cordline is broken. | 5. Replace belt. | |
| BELT BROKEN (Note: Identify and correct problem before new belt is installed) | 1. Incorrect belt tension. | 1. Replace Inspect/Replace tensioner if necessary. |
| 2. Tensile member damaged during belt installation. | 2. Replace belt. | |
| 3. Severe misalignment. | 3. Align pulley(s). | |
| 4. Bracket, pulley, or bearing failure. | 4. Replace defective component and belt. | |
| NOISE (Objectionable squeal, squeak, or rumble is heard or felt while drive belt is in operation) | 1. Incorrect belt tension. | 1. Inspect/Replace tensioner if necessary. |
| 2. Bearing noise. | 2. Locate and repair. | |
| 3. Belt misalignment. | 3. Align belt/pulley(s). | |
| 4. Belt to pulley mismatch. | 4. Install correct belt. | |
| 5. Driven component induced vibration. | 5. Locate defective driven component and repair. | |
| TENSION SHEETING FABRIC FAILURE (Woven fabric on outside, circumference of belt has cracked or separated from body of belt) | 1. Tension sheeting contacting stationary object. | 1. Correct rubbing condition. |
| 2. Excessive heat causing woven fabric to age. | 2. Replace belt | |
| 3. Tension sheeting splice has fractured. | 3. Replace belt. | |
| CORD EDGE FAILURE (Tensile member exposed at edges of belt or separated from belt body) | 1. Incorrect belt tension. | 1. Inspect/Replace tensioner if necessary. |
| 2. Belt contacting stationary object. | 2. Replace belt. | |
| 3. Pulley(s) out of tolerance. | 3. Replace pulley. | |
| 4. Insufficient adhesion between tensile member and rubber matrix. | 4. Replace belt. |
ACCESSORY DRIVE BELT DIAGNOSIS CHART
Scheme 26
| CAUTION | Do not let tensioner arm snap back to the freearm position, severe damage may occur to the tensioner. |
- Disconnect negative battery cable from battery.
- Rotate belt tensioner until it contacts it's stop. Remove belt, then slowly rotate the tensioner (7) into the freearm position.
Scheme 27
- Insert a suitable square drive ratchet into the square hole on belt tensioner arm (7).
- Release the belt tension by rotating the tensioner (7) clockwise . Rotate the belt tensioner (7) until the accessory belt (4) can be removed from pulleys (1,2,3,5,6,8). CAUTION: Do not let the tensioner arm snap back to the freearm position, severe damage may occur to the tensioner.
- Remove the accessory belt (4).
- Gently release the tensioner (7).
Scheme 28
| 1 - IDLER PULLEY |
|---|
| 2 - ACCESSORY DRIVE BELT |
| 3 - P/S PULLEY |
| 4 - RADIATOR FAN PULLEY |
| 5 - CRANKSHAFT PULLEY |
| 6 - ACCESSORY DRIVE BELT TENSIONER |
| 7 - GENERATOR |
| 8 - WATER PUMP |
Scheme 29
- A 1/2 inch square hole is provided in the automatic belt tensioner. Attach a suitable tool into this hole. 1 - IDLER PULLEY 2 - ACCESSORY DRIVE BELT 3 - P/S PULLEY 4 - RADIATOR FAN PULLEY 5 - CRANKSHAFT PULLEY 6 - A/C COMPRESSOR PULLEY 7 - ACCESSORY DRIVE BELT TENSIONER 8 - GENERATOR 9 - WATER PUMP PULLEY
- Rotate tensioner assembly clockwise (as viewed from front) until tension has been relieved from belt.
- Remove belt from water pump pulley first.
- Remove belt from vehicle.
Scheme 30
Scheme 31
- Check condition of all pulleys. CAUTION: When installing the serpentine accessory drive belt, the belt MUST be routed correctly. If not, the engine may overheat due to the water pump rotating in the wrong direction. NOTE: When installing accessory drive belt onto pulleys, make sure that belt is properly routed and all V-grooves make proper contact with pulleys.
- Position accessory drive belt around all pulleys except the idler pulley.
- Rotate the tensioner arm until it contacts it's stop position. Route the belt around the idler and slowly release tensioner rotate into accessory drive belt. Make sure the belt is seated onto all pulleys. 1 - AUTOMATIC TENSIONER ASSEMBLY
- 4.7L Engines Only - With the drive belt installed, inspect the belt wear indicator. Gap between the tang and the housing stop (measurement A) must not exceed 24 mm (.94 inches). If the measurement exceeds this specification replace the accessory drive belt.
DIAGNOSIS AND TESTING - COOLANT CONCENTRATION TESTING
Check coolant concentration when any additional coolant is added to the system, or after a coolant drain, flush and refill. Use of a hydrometer or Refractometer Tool (special tool #8286, Refractometer), refractometer can be used to test coolant concentration.
A hydrometer tests the amount of glycol in a mixture by measuring the specific gravity of the mixture. The higher the concentration of ethylene glycol, the larger the number of balls that will float, and the higher the freeze protection (up to a maximum of 60% by volume glycol).
A Refractometer Tool (special tool #8286, Refractometer) tests 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 manufacturers use other types of glycols into their coolant formulations. Propylene glycol is the most common new coolant. However, propylene glycol based coolants do not provide the same freezing protection and corrosion protection and are not recommended.
| CAUTION | Do not mix types of coolant - corrosion protection will be severely reduced. |
INSPECTION
| WARNING | Do not attempt to bend or straighten fan blades if fan is not within specifications. |
| CAUTION | If fan blade assembly is replaced because of mechanical damage, water pump and viscous fan drive should also be inspected. These components could have been damaged due to excessive vibration. |
DIAGNOSIS AND TESTING - ENGINE BLOCK HEATER
If the unit does not operate, possible causes can be either the power cord or the heater element. Test the power cord for continuity with a 110-volt voltmeter or 110-volt test light. Test heater element continuity with an ohmmeter or a 12-volt test light.
| CAUTION | To prevent damage, the power cord must be secured in its retainer clips and away from any components that may cause abrasion or damage, such as linkages, exhaust components, etc. |
Scheme 32
- Disconnect the battery negative cable.
- Drain the coolant. Refer to «Standard Procedure»(ref-457792-S30781673372012030200000) .
- Remove the power cord from the heater by unplugging.
- Loosen (but do not completely remove) the screw at center of block heater.
- Remove the block heater (1) by carefully prying from side-to-side. Note the direction of the heating element coil (up or down). The element coil must be installed correctly to prevent damage.
DIAGNOSIS AND TESTING - WATER PUMP
A quick test to determine if pump is working is to check if heater warms properly. A defective water pump will not be able to circulate heated coolant through the long heater hose to the heater core.
Inspect the water pump assembly for cracks in the housing, water leaks from the shaft seal, worn bearing or the impeller rubbing either the pump body or the timing chain case/cover.
Scheme 33
| 1 - WATER PUMP |
|---|
| 2 - TIMING CHAIN COVER |
- Clean the gasket mating surfaces.
- Using a new gasket, position water pump and install the mounting bolts. Tighten the water pump mounting bolts to 24 N.m (18 ft. lbs.).
- Spin the water pump to be sure that the pump impeller does not rub against the timing chain case/cover.
- Connect the radiator lower hose to the water pump.
- Install accessory drive belt tensioner. Refer to «TENSIONER, Belt , Installation»(ref-457792-S09501515412012030200000) .
- Install the drive belt. Refer to «BELT, Serpentine , Installation»(ref-457792-S21966014282012030200000) .
- Install the radiator fan. Refer to «FAN, Cooling, Electric , Installation»(ref-457792-S30022413072012030200000) or «FAN, Cooling, Viscous , Installation»(ref-457792-S33156171422012030200000) .
- Evacuate air and refill the cooling system. Refer to «PUMP, Water , Standard Procedure»(ref-457792-S22139213142012030200000) .
- Connect the negative battery cable.
- Check cooling system for leaks. Refer to «Diagnosis and Testing»(ref-457792-S26721215612012030200000) .
DIAGNOSIS AND TESTING - RADIATOR COOLANT FLOW
Use the following procedure to determine if coolant is flowing through the cooling system.
- Idle engine until operating temperature is reached. If the upper radiator hose is warm to the touch, the thermostat is opening and coolant is flowing to the radiator. WARNING: Hot, pressurized coolant can cause injury by scalding. Using a rag to cover the radiator pressure cap, open radiator cap slowly to the first stop. This will allow any built-up pressure to vent to the reserve/overflow tank. After pressure build-up has been released, remove cap from filler neck.
- Drain a small amount of coolant from the radiator until the ends of the radiator tubes are visible through the filler neck. Idle the engine at normal operating temperature. If coolant is flowing past the exposed tubes, the coolant is circulating.
Scheme 34
Scheme 35
Scheme 36
- Disconnect and isolate the negative battery cable.
- Raise and secure the vehicle.
- Drain the cooling system. Refer to «Standard Procedure»(ref-457792-S30781673372012030200000) . WARNING: Do not remove the cylinder block drain plugs or loosen the radiator draincock with the system hot and under pressure. Serious burns from the coolant can occur.
- Remove the lower radiator clamp and hose.
- Remove the lower radiator seal.
- Remove the lower center electric fan to radiator retaining clip.
- Lower the vehicle.
- Remove the upper radiator clamp and hose.
- Remove the upper radiator seal push pins (1).
- Remove the upper radiator seal plastic rivets (2).
- Remove the upper radiator seal.
- If equipped, remove the viscous fan assembly from the water pump hub shaft. Refer to «FAN, Cooling, Electric , Removal»(ref-457792-S13033663812012030200000) or «FAN, Cooling, Viscous , Removal»(ref-457792-S41329399382012030200000) .
- Remove the grille. Refer to «GRILLE , Removal»(ref-457777-S02947677742012030200000) .
- Remove the bolt from the transmission cooler line (1) to radiator (3) bracket (2).
- Remove the washer reserve tank. Refer to «RESERVOIR, Windshield Washer , Removal»(ref-457801-S32322298392012030200000) .
- Remove the coolant overflow/recovery bottle. Refer to «BOTTLE, Coolant Recovery , Removal»(ref-457792-S39427895742012030200000) .
- Remove the front bolts from the A/C compressor/transmission combination cooler (2).
- Remove the upper center electric fan to radiator retaining clip.
- Disconnect the transmission cooler lines from the transmission cooler , then plug the transmission lines and cooler to prevent leakage. Refer to «TUBES AND HOSES, Transmission Oil Cooler , Standard Procedure»(ref-457792-S39844769592012030200000) .
- Disengage the two A/C compressor/transmission combination cooler mounting brackets (2) from the left side of the radiator (1), do not disconnect the A/C lines. After the A/C compressor/transmission combination cooler (3) is disengaged, secure it to the upper radiator support with a strap, cord or equivalent.
- Remove the fan shroud mounting bolts (4) and pull up and out of the radiator tank clips. Position the shroud (1, 2) rearward over the fan blades towards engine.
- Disengage the electric cooling fan (3) to radiator upper retaining clips.
- Disengage the electric fan (3) to radiator lower retaining clips.
- Remove the viscous fan, fan shroud (1, 2) and electric cooling fan (3) as an assembly.
- Remove the two radiator upper mounting bolts (2).
- Lift the radiator (1) straight up and out of the engine compartment. Take care not to damage cooling fins or tubes on the radiator and oil coolers when removing.
Scheme 37
- Remove the upper radiator shroud (1).
- Disconnect and isolate the battery negative cable.
- If equipped, disconnect and isolate the negative battery cable from the auxiliary battery. WARNING: Do not remove the cylinder block drain plugs or loosen the radiator draincock with the system hot and under pressure. Serious burns from coolant can occur.
- Drain the cooling system. Refer to «Standard Procedure»(ref-457792-S30781673372012030200000) .
- Disconnect the ambient air temperature sensor electrical connector and mass airflow sensor electrical connector (If equipped).
- Remove air box and turbocharger inlet tube. Refer to «BODY, Air Cleaner , Removal , 6.7L»(ref-457798-S28601491212012030200000) .
- Remove coolant tank hose from the fastening clips located on top of the radiator.
- Remove the viscous fan and fan shroud. Refer to «FAN, Cooling, Electric , Removal»(ref-457792-S13033663812012030200000) or «FAN, Cooling, Viscous , Removal»(ref-457792-S41329399382012030200000) .
- Remove the hose clamps and hoses from radiator.
- Disconnect the transmission cooler lines at the transmission cooler. The transmission cooler will remain on the radiator and can be removed as an assembly. Refer to «TUBES AND HOSES, Transmission Oil Cooler , Standard Procedure»(ref-457792-S39844769592012030200000) .
- Remove the two radiator upper mounting bolts.
- Lift and support the vehicle.
- Remove the power steering cooler mounting bolts and position the power steering cooler out of the way.
- Lower the vehicle.
- Tilt the radiator towards the rear of the vehicle and lift it out of the engine compartment. The bottom of the radiator is equipped with two alignment dowels that fit into holes in the lower radiator support panel. Rubber biscuits (insulators) are installed to these dowels. Take care not to damage cooling fins or tubes on the radiator and air conditioning condenser or the electronic viscous fan connector when removing.
Inspect the radiator side tanks for cracks, and broken or missing fittings. Inspect the joint where the tanks seam up to the radiator core for signs of leakage and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing cooling fins. Inspect the core for bent or damaged cooling tubes.
DIAGNOSIS AND TESTING - ON-BOARD DIAGNOSTICS
All models are equipped with On-Board Diagnostics for certain cooling system components. Refer to appropriate Engine Performance Electrical Diagnostics article. If the Powertrain Control Module (PCM) detects low engine coolant temperature, it will record a Diagnostic Trouble Code (DTC) in the PCM memory. Do not change a thermostat for lack of heat as indicated by the instrument panel gauge or by poor heater performance unless a DTC is present. Refer to the appropriate Engine Performance Electrical Diagnostics article for other probable causes.
Scheme 38
| 1 - THERMOSTAT HOUSING |
|---|
| 2 - THERMOSTAT LOCATION |
| 3 - THERMOSTAT AND GASKET |
| 4 - TIMING CHAIN COVER |
| WARNING | Do not loosen the radiator draincock with the cooling system hot and pressurized. Serious burns from the coolant can occur. |
- Disconnect the negative battery cable.
- Drain the cooling system. Refer to «Standard Procedure»(ref-457792-S30781673372012030200000).
- Raise and support the vehicle.
- Remove the splash shield.
- Remove the lower radiator hose clamp and the lower radiator hose at the thermostat housing (1).
- Remove the thermostat housing mounting bolts, thermostat housing (1) and thermostat (3). see scheme 139