Hi guys, I was looking for H9DC and ran into this chart which may be helpful.

If we can't find bosch H9DC.

http://www.stormatv.com/Spark_Plug_Specification_Chart_And_Cross_Reference.htm

You'll always be able to get the proper spark plugs at your Mercedes dealer.

They'll probably be Bosch.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Well, not really..Bosch has Stopped making the non-resistor copper core plugs that older (pre mid 90's) Mercedes require. Instead of a W9DC (or DC0) they are now WR9DC etc.. I've already pulled 3 sets of these plugs from cars not running properly after a a few hundred miles. One 450SL and two 560's.

At this point I run the NGK BP6 or BP5 ES's for the V8's depending on what shape the valve guides etc are in.

Jonathan

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Blue Ridge Mercedes
Jonathan Hodgman
http://www.blueridgemb.com/
Enthusiast Service, Restoration & Tuning.
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