Replaced Quick Connect

[Schurkey]

...and in the meantime, the cavitation reduces pump output, leading to overheating. The cooling system may not be filled with froth, but the coolant isn't moving as fast as it should, either.

 

[Donald Mitchell]

You can pretty-much expect to explode the heater core the first time you spin the engine to the upper end of the RPM range.

The quick-connect fitting is restricted to less than a 1/4" diameter, to minimize the pressure/volume delivered to the heater core. Your 3/4" hose nipple will have enormously more flow area.

Considering the Dorman replacement quick-connect is cheap and more durable than the GM original part, it's crazy to not keep the quick connector.

I just don't understand how that can happen, worked on chevys all my life and none had a restricted heater fitting and none exploded. Not saying your wrong but I cant imagine it happening.