Hey Guys,
My 89 420 started missing yesterday and I pulled out one of the spark plugs and it only says BOSCH PLATINUM, no printed number.
The dealer has always tuned the 420 before I retired, but now I have the time and I want to do it. I have always checked the plugs number when I have serviced my other cars in the past, but this is the first time for me to do the 420, and I see no BOSCH number. I figured the dealer has certain plugs he used, but these don't help me.

I'm going to the parts store tomorrow, and I wanted this boards input on which spark plugs to buy and everyones opinion.

It's a 1989 S420 with 155K miles and always runs Chevron 93 octane
gas, (As the dealer had reccomended).

Thanks

I'm not sure if it's the same for the S-class but I know the platinum plugs aren't recommended for the older E-class engines. They use the Bosch copper plugs.

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1993 320TE M104
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past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
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"music and women I cannot but give way to, whatever my business" -Pepys

It is common for Bosch Platinums to have their number ( could be just a 4-digit number ), " engraved " on the metal shell, NOT on the ceramic insulator.
When in doubt, get your vendor to look up the proper plug in his Bosch catalogue.

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2007 C 230 Sport.

Use Bosch W8DCO

Gilly

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