I GM 10 overheating ?

[john aellen]

Always a mystery ripping things off the motor waiting to discover where a water line blockage may appear.  This time was no different.  Two  blades broke off the impeller.  One actually lodged in the upstream ( raw water) supply tube inside the bronze housing.  I thought it was all fixed.   No - that would just be too easy.

Had this happen once before, so I stuck a flat blade screw driver into the metal "T" pipe that goes into the block from the water pump.  You need a long screwdriver to get all the way in to the cylinder wall - most are too short.  A phillips screwdriver would work too.     I found a reamer in my workshop that is the exact fit to remove scale and gunk that builds up in that supply tube.  It is 5/32 ID.  A long drill bit would probably work too. 

This is the second time I have had to clear out a blockage on that intake port.

Will test drive it this week.