When I answered this query earlier I didn’t mention the two days of misery I spent in a Louisiana La Quinta parking lot trying to find the miserable tiny coolant leak. I finally found the leak by using the cooling system pressure tester when I got back to Texas. While on the road and desperate to reach my sons house in NY by Christmas, what I finally did was use a high-powered stop-leak (knowing that it could harm my cars heater). The stop-leak did work for most of the 3,000 mile R/T, but sure enough it did damage my cars heater. The heater still works but not nearly as well as it did before I added the stop-leak to the system. I’m hoping that since I’ve flushed out the system and replaced the fluids that the heater will eventually return to its former efficiency.
I would only recommend using stop-leak as a desperate measure.
Steve