What's behind this plug? 2001 4.3L

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,443
Finally got the flywheel off on my slow motion RMS replacement. Found a plug just above the crankshaft that's ferrous (others on the block were brass already). I don't think its a water passage but want to make sure before I button it back up.

IMG_20250505_160836.jpg
 
Top