928 S V8-4957cc 5.0L (1985)
Below is a listing of all tested and approved spark plugs.
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spark plug tightening torque: 30 N-m (21.6 ft. lbs.)
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it is recommended to lubricate the threads of spark plugs lightly with graphite grease (Molykote paste HTP white), or equivalent, prior to
installation. Make sure paste is kept off the electrodes and the inside of the spark plug!
Resistor Type Spark Plugs
Resistor spark plugs are used since M.Y. 1985 to eliminate radio interference. These spark plugs may also be used in older models. Resistor spark
plugs can be identified by the "R" in the type designation, e.g. WR7DC.
Bosch Platinum Spark Plugs
Spark plugs designated with the lefters "DPO", or W3DPO on the new Bosch spark plug Designation System correspond with the conventional
design platinum spark plugs from the old system which were W28OP21.
Spark plugs with the lefters "DP" or CP or W5DP or W3DP are platinum spark plugs of the new design with a sintered center electrode. These
spark plugs must not be installed when conventional design platinum spark plugs "P21" or "DPO" only are specified.
ORDERING INFORMATION
Bosch
to
Porsche
W3CC
999 170 162 90
W3DP
Use W3DPO
W3DPO
999 170 128 90
W4CS
999 170 140 90
W4DPO
999 170 008 90
W5DC
999 170 165 90