MD7A raw water cooling

Oct 2, 2005
465
The raw water cooling channels on my Volvo MD7A have apparently
become blocked. Raw water cooled, no exchanger. The temp gage won't
register heat. I changed the thermostat and then the sensor . . . and
then discovered the block is getting warm but the exhaust water at the
stern is cold. I am hoping the blockage, rust, can be cleared by
removing the cold water unit the thermostat is mounted on but . ..
Have others had this problem? The books say there should be a zinc on
the engine but I can't find one, and the manual doesn't mention it.
Does someone know where it is? Thanks
Craig Tern #1519