glowplug removal merc OM642

[Trustmeimadoctor]

any advice at all? seems i have one or more gone so im looking at doing them BUT i see many horror storys when replacing them any advice at all?

[Trustmeimadoctor]

no idea really havent tested the plugs need to do that first i suppose

[Trustmeimadoctor]

What value should working plugs give when i test them?