[1991 Corvette ZR-1]

Thanks, Craig. Some patience and the use of a large EZ out, along with a 7/8 reamer bit has yielded some results. But not optimal, I do not advocate the method I used. I can now get about three full threads engaged before the new fitting butts against the remnants of the old fitting stuck inside still. I might try a machine shop, but not sure if they can do anything else without destroying the female threads in the process. And I cannot push more of the reamer bit in without wiping out the threads. Maybe three full threads is good with a quality sealant?

My Z has 98K miles, so if any owners reading this are in or near the same ballpark for mileage and you notice a leak from the heater hose nipple, hope you know a good machine shop. The Dorman part number for the replacement retainers is 800-407. It is a two pack that comes with a retainer for the heater hose return pipe and one for the coolant reservoir hose connection to the thermostat.