6.7L Diesel Engine - Service Information: Overview RAM Pickup 2500

DESCRIPTION

The cylinder block is constructed of cast iron. The casting is a skirted design which incorporates longitudal ribs for superior strength and noise reduction. The block incorporates metric straight thread O-ring fittings at lubrication oil access points. The engine is manufactured with the cylinders being a non-sleeved type cylinder.

Scheme 490

The cylinders are numbered front to rear; 1 to 6. The firing order is 1 - 5 - 3 - 6 - 2 - 4.

The unique intake and exhaust rocker arms have their own rocker shafts and are lubricated by passages intersecting the cylinder block main oil rifle. Crossheads are used, which allow each rocker arm to operate two valves.

The solid push rods are hardened at the rocker arm and tappet contact areas for superior strength and durability.

Scheme 491

Scheme 492

1. Disconnect both negative battery cables.
2. Remove cylinder head cover. Refer to «COVER(S), Cylinder Head , Removal , 6.7L»(ref-457798-S18243865832012030200000) .
3. Remove the rocker arm/pedestal fasteners and remove rocker arm (1) and pedestal (2) from cylinder head. Mark the arms and pedestals so they can be installed in their original position. CAUTION: When removing the rocker arms, the sockets may come loose and fall into the engine. Make sure they stay with the arm upon removal/installation.
4. Lift the push rod(s) up and out of the engine. Mark them so they can be installed in their original position. NOTE: The No. 5 cylinder intake and exhaust, and No. 6 cylinder intake and exhaust push rods must be raised through the provided cowl panel access holes.
5. Lift the crossheads off of the valve stems. Mark them so they can be installed in their original position.

A gear driven gerotor type oil pump is mounted behind the front gear cover in the lower right portion on the engine.

OPERATION

A gerotor style oil pump draws oil from the crankcase through the suction tube and delivers it through the block where it enters the oil cooler cover and pressure regulator valve. When oil pressure exceeds 517 kPa (75 PSI), the valve opens exposing the dump port, which routes excess oil back to the oil pump.

At the same time, oil is directed to a cast in passage in the oil cooler cover, leading to the oil cooler element. As the oil travels through the element plates, it is cooled by engine coolant traveling past the outside of the plates. It is then routed to the oil filter head and through a full flow oil filter. If a plugged filter is encountered, the filter by-pass valve opens, allowing unfiltered oil to lubricate the engine. This condition can be avoided by frequent oil and filter changes, per the maintenance schedules found in the owners manual. The by-pass valve is calibrated to open when it sees a pressure drop of more than 345 kPa (50 psi) across the oil filter.

The oil filter head then divides the oil between the engine and the turbocharger. The turbocharger receives filtered, cooled and pressurized oil through a supply line from the filter head. The oil lubricates the turbocharger and returns to the pan by way of a drain tube connecting the bottom of the turbocharger to a tube in the cylinder block.

Scheme 493

Oil is then carried across the block to an angle drilling which intersects the main oil rifle (3). The main oil rifle (3) runs the length of the block and delivers oil to the crankshaft main journals and valve train. Oil travels to the crankshaft through a series of transfer drillings (one for each main bearing) and lubricates a groove in the main bearing upper shell. From there another drilling feeds the camshaft main journals. J-jet piston cooling nozzles (1,4) are supplied by a separate oil rifle. Plugs are used in place of saddle jets when J-jets are used. Crankshaft internal cross-drillings supply oil to the connecting rod journals.

Scheme 494

Another series of transfer drillings intersecting the main oil rifle supply (14) the valve train components. Oil travels up the drilling, through a hole in the head gasket, and through a drilling in the cylinder head (one per cylinder), where it enters the rocker arm pedestal (3) and is divided between the intake and exhaust rocker arm (1). Oil travels up and around the rocker arm mounting bolt, and lubricates the rocker shaft (2) by cross drillings that intersect the mounting bolt hole. Grooves at both ends of the rocker shaft supply oil through the rocker arm where the oil travels to the push rod and socket balls.

The charge air system consists of the charge air cooler piping, charge air cooler and intake air grid heater.

The Charge Air Cooler is a heat exchanger that uses air flow from vehicle motion to dissipate heat from the intake air. As the turbocharger increases air pressure, the air temperature increases. Lowering the intake air temperature increases engine efficiency and power.

Scheme 495

Low turbocharger boost pressure and low engine performance can be caused by leaks in the charge air cooler or plumbing. Fuel staining on the exhaust manifold can also be an indication that there are leaks in the air system. The following procedure outlines how to check for leaks in the charge air cooler system.

This procedure can also be used to check for leaks in the wastegate signal line or the wastegate canister.

1. Loosen clamp and remove air inlet hose from turbocharger.
2. Insert CAC Tester Tool (special tool #10137, Adapter, Charge Air) into the turbocharger inlet. Tighten tool clamp to 8 N.m (72 in. lbs.). CAUTION: Do not apply more than 138 kPa (20 psi) air pressure to the charge air cooler system, severe damage to the charge air cooler system may occur.
3. Connect a regulated air supply to air fitting on CAC Tester (special tool #10137, Adapter, Charge Air). Apply 27.5 - 55 kPa (4 - 20 psi) to Tool (special tool #10137, Adapter, Charge Air).
4. Using MOPAR® Air Leak Detector, check the rubber sleeves, clamps, charge air cooler and intake manifold for leaks.
5. Using MOPAR® Air Leak Detector check for leaks at the wastegate signal line, wastegate canister and wastegate command valve.

Scheme 496

1. Disconnect the battery negative cables.
2. Discharge the A/C system and remove the A/C condenser (if equipped). Refer to «Plumbing , Standard Procedure»(ref-457787-S01365783702012030200000) and «CONDENSER, A/C , Removal»(ref-457787-S16872234702012030200000) .
3. Remove the front grille assembly. Refer to «GRILLE , Removal»(ref-457777-S02947677742012030200000) .
4. Remove the transmission auxiliary cooler. Refer to «COOLER, Transmission Oil , Removal»(ref-457792-S23821098932012030200000) .
5. Remove the intake air tubing (4) from the charge air cooler (2).
6. Remove the charge air cooler bolts. Pivot the charge air cooler (2) forward and up to remove.

TURBOCHARGER OPERATION

The turbocharger is water cooled and lubricated by engine oil that is pressurized, cooled, and filtered. The oil is delivered to the turbocharger by a supply line that is tapped into the oil filter head. The oil travels into the bearing housing, where it lubricates the shaft and bearings. A return pipe at the bottom of the bearing housing, routes the engine oil back to the crankcase.

Exhaust gas enters the turbine section of the turbocharger as it leaves the combustion chamber. Heat and pressure are extracted from the exhaust gas and cause the turbine to rotate. The turbine is connected by shaft to the compressor section of the turbocharger. The rotating compressor draws in inlet air, compresses it and sends the compressed air through the Charge Air Cooler to the engine.

The Variable Geometry Turbocharger (VGT) uses a one piece sliding nozzle that moves continuously to vary the power of turbine and the amount of air delivered to the engine. This allows turbine power to be set to provide just enough energy to drive the compressor at the desired boost level in all engine operating modes.

Turbine power level changes are achieved by varying the position of the nozzle ring in relation to a set of guide vanes that control the flow through the turbine. An electrically controlled actuator positions the sliding nozzle over the guide vanes.