[camachinist]

You can always disable all the accessories by removing the belts and then attempt to duplicate the problem. The engine can run for 3-5 minutes, when started cold, without a water pump with no problem.

Did you buy this as an engine/trans unit or just the engine?

If the sound is metallic, likely it's caused by something amiss in the marriage of engine and trans...

Get back to us....

 

[camachinist]

The 3-5 minute window was a conservative estimate, based on how long it takes the race car engine to get to 180 with the water pump off...and running at a modest rpm (2000 or so)

YMMV...*G*