Scheme 48
The 3.6 liter (219.7 CID) flexible fuel V-6 engine features Variable Valve Timing (VVT), Dual Overhead Camshafts (DOHC) and a high-pressure die-cast aluminum cylinder block with steel liners in a 60° configuration. The 3.6 liter engine has a chain driven variable discharge oil pump with a two-stage pressure regulator for improved fuel economy. The exhaust manifolds are integrated into the cylinder heads for reduced weight. The cylinders are numbered from front to rear. The right bank is numbered 1, 3, 5 and the left bank is numbered 2, 4, 6. The firing order is 1-2-3-4-5-6. The engine serial number is located on the left side of the cylinder block at the transmission flange.
ENGINE DIAGNOSIS - INTRODUCTION
Engine diagnosis is helpful in determining the causes of malfunctions not detected and remedied by routine maintenance.
These malfunctions may be classified as either performance (e.g., engine idles rough and stalls) or mechanical (e.g., a strange noise).
Refer to ENGINE PERFORMANCE DIAGNOSTIC TABLE and ENGINE MECHANICAL DIAGNOSTIC TABLE for possible causes and corrections of malfunctions.
Refer to FUEL SYSTEM article, for the fuel system diagnosis.
Additional tests and diagnostic procedures may be necessary for specific engine malfunctions that can not be isolated with the Service Diagnosis charts. Information concerning additional tests and diagnosis is provided within the following diagnosis
- Cylinder Compression Pressure Test. Refer to «CYLINDER COMPRESSION PRESSURE LEAKAGE»(ref-465933-S40221837532012042300000) .
- Cylinder Combustion Pressure Leakage Test. Refer to «CYLINDER COMBUSTION PRESSURE LEAKAGE»(ref-465933-S08656615382012042300000) .
- Engine Cylinder Head Gasket Failure Diagnosis. Refer to «CYLINDER HEAD GASKET»(ref-465933-S30014234922012042300000) .
- Intake Manifold Leakage Diagnosis. Refer to «INTAKE MANIFOLD LEAKS»(ref-465933-S05005148392012042300000) .
DESCRIPTION
The oil cooler is attached to the top of the oil filter housing which is located in the V of the cylinder block. The oil cooler is a plate style coolant-to-oil heat exchanger.
OPERATION
Oil flows from the engine oil pump to the oil filter housing inlet (1) and to the oil filter element located within the oil filter housing. After the oil is filtered it travels internally through the engine oil cooler and then to the main oil gallery (5).
Coolant flows from the right cylinder block water jacket (3) and from the left cylinder block water jacket (4) into the housing. The coolant flows through the oil cooler and exits the housing from the rear hose nipple (6) where it is returned to the water pump. A coolant by-pass in the housing is designed to direct excessive coolant flow around the oil cooler for continuous circulation.
The oil pressure sensor (2) is located on the oil filter housing (3). The oil pressure sensor is a three wire sensor with a tapered threaded sensor port. The sensor port is mounted to the oil filter housing through an access hole. A thread lock patch seals the oil pressure sensor to the oil filter housing.
Scheme 49
The oil pressure sensor is a silicon based sensing unit that measures the pressure of the engine oil. The Powertrain Control Module (PCM) supplies a 5 volt reference and a ground to the sensor. The input to the PCM occurs on the signal return circuit. The oil pressure sensor is a linear sensor; as pressure changes, voltage changes proportionately and returns a voltage signal to the PCM that reflects oil pressure. The zero pressure reading is 0.5 volt and full scale is 4.5 volt.
Scheme 50
- Release fuel system pressure. Refer to «FUEL DELIVERY, GAS , STANDARD PROCEDURE»(ref-465971-S02093746452012042300000) .
- Disconnect and isolate the negative battery cable.
- Remove the air inlet hose, upper intake manifold and lower intake manifold with the fuel injectors and fuel rail (2). Refer to «MANIFOLD, INTAKE , REMOVAL»(ref-465933-S24442072442012042300000) .
- Disconnect the oil pressure sensor electrical connector (4).
- Remove the oil pressure sensor (2) from the oil filter housing (3).
The oil temperature sensor (1) is located on the oil filter housing (3). The oil temperature sensor is a two wire sensor with a tapered threaded sensor probe. The sensor probe is mounted to the oil filter housing through an access hole. A thread lock patch seals the oil temperature sensor to the oil filter housing.
Scheme 51
The oil temperature sensor is a variable resistor that measures the temperature of the engine oil. The Powertrain Control Module (PCM) supplies a 5 volt reference and a ground to the sensors low reference signal circuit. When the oil temperature is low, the sensor resistance is high. When the oil temperature is high, the sensor resistance is low.
The 3.6L aluminum cylinder heads are a unique design with left and right castings. The exhaust manifolds are integrated into the cylinder heads. If any damaged is found to the exhaust manifold portion, the cylinder head must be removed for repair or replacement. Refer to CYLINDER HEAD , REMOVAL .
Scheme 52
The timing drive uses four silent chains. The silent chain link design improves sprocket engagement and reduces noise, vibration and harshness (NVH). One chain (5) drives the oil pump (4) and three chains drive the camshafts in a two stage design. The left secondary camshaft chain (1) uses an oil pressure controlled chain tensioner (9) with a ratcheting device. The right secondary camshaft chain (8) uses an oil pressure controlled tensioner (7) without a ratchet. The primary chain (2) also uses an oil pressure controlled tensioner (6) without a ratchet. A spring loaded tensioner (3) takes up the slack in the oil pump chain (5). The chain guides and tensioner arms are made of glass filled nylon with nylon wear faces.
Scheme 53
The primary timing chain is a silent type. The primary chain drives the 28 tooth idler sprocket directly from a 21 tooth crankshaft sprocket. This results in a 75% speed reduction to the idler sprocket. The idler sprocket assembly connects the primary chain drive and the secondary chain drive. The idler sprocket assembly consists of two integral 22 tooth sprockets a 28 tooth sprocket. The idler sprocket assembly spins on a stationary idler shaft. The idler shaft is a light press-fit into the cylinder block. A large washer on the idler shaft bolt and the rear flange of the idler shaft are used to control sprocket thrust movement. Pressurized oil is routed through the center of the idler shaft to provide lubrication for the bushings used in the idler sprocket assembly. Primary chain motion is controlled by a hydraulic oil damped tensioner and a fixed guide. The tensioner and the guide both use nylon plastic wear faces for low friction and long wear. The primary chain receives oil splash lubrication.
Scheme 54
There are two identical secondary drive chains, both are silent type, one to drive the camshafts in each double overhead cam (DOHC) cylinder head. The secondary chains drive the 33 tooth camshaft sprockets directly from the 22 tooth idler sprockets. This speed reduction combined with the crankshaft to idler sprocket speed reduction produces the required 2:1 camshaft drive ratio. A fixed chain guide and a hydraulic oil damped tensioner are used to maintain tension in each secondary chain system. The left hydraulic secondary chain tensioner is fed from the main oil gallery through the cylinder head. The right hydraulic secondary chain tensioner is fed from the number one main bearing journal. Each tensioner incorporates a controlled leak path through a device known as a vent disc located in the nose of the piston to manage chain loads. Only the left tensioner has a mechanical ratchet system that limits chain slack if the tensioner piston bleeds down after engine shut down. The tensioner arms and guides also utilize nylon wear faces for low friction and long wear. The two secondary timing chains are lubricated by holes in the oil controlled tensioners that spray oil through an opening in the tensioner arms. The holes are protected from clogging by a fine mesh screen which is located on the back of the hydraulic tensioners.
Scheme 55
The left side cam chain tensioner used on the 3.6L engine is equipped with a ratchet. The ratchet consists of a rack (2) and a pawl (1). In use, the rack (2) extends with the piston (3) from the tensioner body. The pawl (1) will not allow the rack (2) to retract back into the tensioner body. In order to reset the tensioner, the pawl (1) must be disengaged from the rack (2) so that the piston (3) and rack (2) can be pushed back (4) into the tensioner body.
Scheme 56
Note. The slot (2) in the rack provides an anchor point for a pin that holds the rack in the retracted position.
Scheme 57
- Using a suitable tool, such as an allen wrench (1), lift the pawl off of the rack.
- While holding the pawl off of the rack, push the rack and the piston into the tensioner body.
- When the slot is aligned with the hole in the tensioner body, insert Tensioner Pin (special tool #8514, Pins, Tensioner) (1) to hold the rack and piston in the retracted position.