The purpose of New Product Information is to highlight
important technical changes from the previous model year.
Changes may include one or more of the following items:
| • | Torque values and/or fastener tightening strategies |
| • | Changed engine specifications |
| • | New sealants and/or adhesives |
| • | Disassembly and assembly procedure revisions |
| • | Engine mechanical diagnostic procedure revisions |
| • | New special tools required |
| • | A component comparison from the previous year |
Torque Values and/or Fastener Tightening Strategies
| • | Cylinder head, connecting rod, and crankshaft bearing cap bolts
now apply a torque angle strategy. |
| • | Certain fasteners should not be reused. Bolts, studs, or other
fasteners that must be replaced will be called out in the specific service
procedure. |
| • | The Crankshaft Balancer bolt has a much higher torque specification. |
Changed Engine Specifications
| • | Crankshaft stroke has changed, bringing displacement to 8.1 L
(496 cubic inches). |
| • | Refer to Engine Mechanical Specifications. |
New Sealants and/or Adhesives
| • | An anaerobic gasket maker is used to seal the rear crankshaft
bearing cap to the engine block. |
| • | A pipe sealant type material is used on the engine coolant and
oil gallery plugs, oil pressure sensor threads, and engine oil cooler fittings. |
| | Refer to Sealers, Adhesives and Lubricants. |
Disassembly and Assembly Procedure Revisions
The majority of the disassembly and assembly procedures have been revised,
due to the newly designed engine assembly.
Engine Mechanical Diagnostic Procedure Revisions
Base Engine Misfire and Engine Noise Diagnosis information is now provided
in table form. Potential or probable causes are supplied for each specific
concern.
Refer to A Diagnostic Starting Point - Engine Mechanical.
New Special Tools Required
A variety of new tools have been developed to assist in engine disassembly,
assembly, and on-vehicle service.
Refer to Special Tools.
A Component Comparison from the Previous Year
| • | The 8.1 liter, L18 engine has replaced the 7.4 liter,
L29/LP4/L21 engines. |
| • | Some of the new features include: |
| - | The L18 has a cast aluminum one piece intake manifold. The 7.4 L
has a two piece design. |
| - | The L18 ignition system includes a crankshaft sensor, front cover
mounted camshaft sensor, and eight individual ignition coils, similar to the
LP4/L21. |
| - | The L18 uses a coolant crossover pipe to route coolant from the
left to right cylinder head. The 7.4 L allowed coolant to crossover
through the intake manifold. |
| - | The thermostat is located on the coolant crossover pipe. |
| - | The L18 has a rear-mounted, non-replaceable reluctor ring for
the crankshaft position sensor. |
| - | The L18 crankshaft position sensor is located on the left rear
of the engine block. |
| - | The L18 utilizes an oil deflector for the crankshaft. |
| - | The L18 does not have engine block expansion plugs on the sides
of the engine block. |
| - | The L18 has an internal Positive Crankcase Ventilation (PCV) system,
and does not utilize a PCV valve. |
| - | The L18 uses an Electronic Throttle Control (ETC) throttle body. |
| - | The L18 uses a cassette-style seal for the rear of the crankshaft. |
| - | The L18 uses studs and nuts to retain the valve rocker arms. The
7.4 L used bolts to retain the valve rocker arms. |
| - | The L18 uses positive valve stem seals mounted over the cylinder
head valve guides. |
| - | The L18 does not have a distributor or rear mounted camshaft position
sensor. |
| - | The L18 uses an oil pump drive that is mounted to the engine block,
under the intake manifold, where the distributor was previously located. |
| - | The L18 uses a roller ball pilot bearing for manual transmissions.
The 7.4 L used a needle bearing. |
| • | Refer to Disassembled Views and Engine Component Description. |
