I opened the monvalve compartment and found it full of coolant. Time for replacement? And if so, does the silver-colored metallic cylinder into which the monovalve fits need replacing also?
Thanks.

Do you mean that you removed the monovalve catridge and there was coolant in the cavity? If so, there's supposed to be coolant in there. You'll lose anywhere from two tablespoons to a quarter cup of coolant when you work on the monovalve cartridge.

Sixto
91 300SE
87 300SDL
83 300SD

That "the silver-colored metallic cylinder" IS the plunger you replace with the "monovalve repair kit."

__________________
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I did a more thorough search and found Phillip Fox's site - all I needed. Thanks Phillip!

http://mbdieseldiy.tripod.com/monovalve.htm