GM Gasoline V6 90 Degree - Manual (Page 26)

ENGINE APPLICATION MANUAL GM Powertrain
Gasoline 4.3L V6 90 Degree Revised: 08/15/2000
File: c:\data\manuales\v6-truck\am43v6#3.doc
Contact:Luis Nespolo - (248) 857-1558 Printed: 8/15/00 24
3.1.6.2 Back Pressure
Exhaust back pressure shall not exceed 8.5 inches of Hg at rated speed and load. Lower
exhaust back pressure is desired from a performance and fuel economy standpoint.
3.1.6.3 Packaging
The vehicle assembly plant attaches the exhaust pipe to the manifold with the proper
fasteners and a gasket or seal. Exhaust manifold takedowns will be 2 or 3 fastener designs.
Consult GM application engineer.
The current exhaust manifolds are made from Nodular Iron with incorporated and
detachable heat shields.
Fasteners at the manifold takedown must be capable of withstanding temperatures up to
800°C and will require stainless steel or sermagard coated steel. The gasket/seal must also
withstand these temperatures and will require stainless steel or stainless steel with mica or
grafoil.
The heat shield provided on the exhaust manifold will reduce radiant heat to nearby critical
components and reduce or minimize the number of separate shields required by the vehicle.
3.1.6.4 Exhaust Gas Recirculation (EGR)
EGR P-Truck C/K Truck G-Van M/L -Van S/T Truck
( 6 L 3 )
EGR ASM Valve 17200268 17200268 17200268 17200268 17200268
3.1.6.5 Secondary Air
GMPT will indicate the needs for secondary air recirculation.
The following table shows the different Secondary Air and EGR Assemblies and
Components coupled to the L35 engine per GM platforms.
Engine Secondary Air P-Truck C/K Truck G-Van M/L -Van S/T Truck
( 6T )
Pump Air Inj ASM 15059238 15053709 15056764
Hose ASM 15022544 N/A 15023825
Hose ASM By Pass 15022570 N/A 15760279
Stud 20513798 N/A
Washer 15953691
Strap 11509086
Bolt Screw 11508706
Pipe ASM 12561825 12562572 12561250/51
Check Valve (or Bypass) 12567731 12567745 15037955
Check Valve (or Bypass) 12567732 12567746 15056713
Bolt Screw 12558020 11515210 15695050
9440034
Gasket 12561871 12561871 12561871
Shield 15026631
Nut 11514596