Fleetwood V6-252 4.1L VIN 4 4-BBL (1982)
Spark Plug: Technical Service Bulletins
Spark Plug - New Design
Bulletin No.
T-88-70
File in Group
6D
Number
37
Corp. Ref. No.
816402
Date
Jan. '88
SUBJECT:
SPARK PLUG SERVICE
MODELS AFFECTED: 1982-1988 CADILLACS WITH 4.1L OR 4.5L ENGINES
Beginning in the 1988 model year, a new AC spark plug has been released for all Cadillac 4.1L and 4.5L engines to improve the spark plug to spark plug
boot interface. It is important that service technicians understand the reasons behind the selection of this new spark plug.
With the introduction of silicone spark plug wire boots several years ago, the tendency for a bonding or sticking condition to develop between the spark
plugs and the spark plug boots began to arise. This condition arose because the silicone wire boot and the spark plug outer ceramic are similar materials.
Exposure to underhood temperatures over periods of time increases the bond between the boot and the spark plug ceramic. In the past, different
lubricative materials have been used in the spark plug boots with varying success. The new spark plug for 1988 was released to address this bonding
condition.
FIGURE 1 - SPARK PLUG IDENTIFICATION
1988 production spark plugs have a lubricative boot release coating baked onto the spark plugs ceramic outer surface. This coating is clear with a
slightly waxy feel. To help identify the coated spark plug, the green rings were removed from the upper portion of the ceramic as a running change
(Figure 1). To further identify the new spark plug, the type number has been changed from .R44LTS6 to .R44LTS6K.
Test results have shown that the coating provides a significant reduction in spark plug boot release effort. Cadillac's 4.1L and 4.5L engines, along with
the Oldsmobile Quad 4 engine, will be the only engines to use a coated plug of this type in 1988 production. In addition, Cadillac will be the only GM
division to offer a coated spark plug for service use.
FIGURE 1 - SPARK PLUG IDENTIFICATION
