Suburban 1/2 Ton 2WD V8-350 5.7L (1986)
Spark Plug: All Technical Service Bulletins
Spark Plug - Revised Application Chart
Number:
86-137
Section:
6D
Date:
AUG., 1986
Subject:
SPARK PLUG USAGE
Model and Year:
1986 LIGHT DUTY VEHICLES WITH GAS ENGINES
TO:
ALL CHEVROLET DEALERS
The following information is being provided to assist dealers in the correct spark plug usage in 1986 Light Duty Trucks. Starting in 1986 many spark
plug usages were changed. If it becomes necessary to replace the spark plugs, use the chart below for the correct plug application. It is not recommended
that higher heat range plugs (example R43CTS to R44CTS) be substituted to try to correct a driveability complaint as installation of higher heat range
plugs can cause engine damage.
MODEL
ENGINE
VIN CODE
SPARK PLUG
GAP
P/N
S/T
2.5L
E
R43CTS6
0.060
5613812
S/T
2.8L
R
R43CTS
0.045
5613810
M Van
2.5L
E
R43CTS6
0.060
5613812
M Van
4.3L
Z
R43CTS
0.035
5613810
C,K,G
4.3L
N
R43CTS
0.035
5613810
C,K,G
4.8L
T
R44T
0.035
5613867
C,K,G
5.0L
H,F
R43CTS
0.045
5613810
C,K,G
5.7L
L,M
R43CTS
0.045
5613810
C,K,G
7.4L
W
R44T
0.045
5613867
NOTE:
Spark plugs should be ordered by part numbers. The plug type designation for a given part number may carry either a "C" or a dot to indicate a
copper core electrode. AC-Delco is in the process of eliminating the "C" designation, and replacing it with a dot in all copper core plugs.
