Suburban 3/4 Ton 2WD V8-454 7.4L (1985)
Exhaust Manifold: Customer Interest
Exhaust Manifold - Leaks
Number:
REISSUE 86-255-6F
Section:
6F
Date:
JUNE, 1988
Subject:
EXHAUST MANIFOLD LEAKS
Model and Year: 1981-86 C/K TRUCKS, P CHASSIS AND MOTORHOME CHASSIS EQUIPPED
WITH 7.4L (VIN W) ENGINES AND CAST IRON EXHAUST MANIFOLDS
TO:
ALL CHEVROLET DEALERS
Chevrolet Dealer Service Bulletin 86-255-6F, dated November, 1987, is being revised to correct the labor operation number for the right side repair. All
copies of 86-255-6F dated November, 1987 should be discarded.
Some 1981-86 trucks with 7.4L engines and cast iron exhaust manifolds may experience a condition where an exhaust leak develops between the
manifold and the cylinder head mating surface causing a noise condition.
Starting in 1987, an improved cast exhaust manifold using nodular iron instead of grey iron was released on the 1987 R/V trucks with the 7.4L engine.
The nodular iron manifold is less susceptible to heat warpage than the previously used grey iron exhaust manifold. This manifold can be used to repair
leaking exhaust manifolds on earlier year trucks and motorhomes. This manifold is NOT interchangeable with tubular manifolds used with the H5D
(Federal Emissions NA5/NA6 equipped trucks built after January 1, 1985, with Heavy Duty Emissions and dual air pumps) emission system. To install,
the following parts are required:
PART NO.
USAGE
QUANTITY
14103191
Manifold-Exhaust LH
1
10045732
Manifold Assembly-
1
Exhaust RH
14053573
Stud-Exhaust
3
Manifold LH
PART NO.
USAGE
OUANTITY
14053574
Stud-Exhaust
3
Manifold RH
587575
Spring-Exhaust Manifold
6
9422297
Nut-Exhaust Manifold
6
(3/8-16)
120395
Washer-Exhaust Manifold
6
(3/8 Flat)
15592451
Seal Assembly -
2
Exhaust Manifold
3909821
Bolt-Exhaust Manifold
16
(3/8 x 1-3/16)
10017198
Plug-Oxygen Sensor (18 mm)
1
LH Side
5617102
Gasket-Oxygen sensor
1
Plug LH Side
10068600
Shield-Starter
1
9439915
Nut-Starter Shield
2
(1/4-20)