New Product Information for Chevrolet Express 2008
The purpose of New Product Information is to highlight, or indicate, important product changes from the previous model year.
Changes may include 1 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 |
Changed engine Specifications
Engine mechanical specification tables have been added for the new design LY2, LMF, and LY6 engines. Refer to
Engine Mechanical Specifications
.
Torque Values and/or Fastener Tightening Strategies
| • | All fasteners and threaded holes on the LY2, LMF, and LY6 engines utilize metric threads. |
| • | Cylinder head, connecting rod, crankshaft balancer, camshaft sprocket, and main bearing cap bolts now apply a torque angle tightening strategy. |
| • | Certain fasteners should not be used again. Bolts, studs, or other fasteners that must be replaced, will be called out in the specific service procedure. |
| • | For the LY2 and LMF applications, the camshaft sprocket is now retained to the front of the camshaft using a single bolt design with a torque and angle tightening strategy. Refer to
Fastener Tightening Specifications
. |
| • | For the LY6 application, the camshaft position actuator is now retained to the front of the camshaft using a single bolt/valve design with a torque and angle tightening strategy. Refer to
Fastener Tightening Specifications
. |
New Sealants and/or Adhesives
Sealers and adhesives, as required, are identified within the specific service procedures. Refer to
Adhesives, Fluids, Lubricants, and Sealers
.
Disassembly and Assembly Procedure Revisions
A variety of procedures have been revised based on the new design LY2, LMF, and LY6 engines.
Engine Mechanical Diagnostic Procedure Revisions
Diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system condition. The diagnostic flow is the place to start
when repairs are necessary. For a detailed explanation, refer to
Diagnostic Starting Point - Engine Mechanical
.
New Special Tools Required
Timing belt tensioner retaining pin
EN 46330
is used to retain the timing chain tensioner during the installation procedure.
A Component Comparison from the Previous Year
| • | The 4.8L LR4 VIN V Gen 3 engine is replaced by the 4.8L LY2 VIN C Gen 4 engine. |
| • | The 5.3L LM7 VIN T and L59 VIN Z Gen 3 engines are replaced by the 5.3L LMF VIN 4 Gen 4 engine. The LMF application is E85 fuel compatible. |
| • | Second design engines will use a rivet-type plug replacing the coolant air bleed covers located at the top rear of each cylinder head. To properly repair a leaking plug, remove cylinder head from the engine, remove the plug from the cylinder head
and install first design coolant air bleed cover and bolt. |
