1997 SLS coolant leak

Just had the radiator/cooling system flushed by the dealer at 100,000 miles and I have now developed a small leak on the right hand side of the radiator, just where the plastic end cap is affixed, near the top.
Leaks coolant about one 2 pints per day.

Any way I can seal this leak without removing the radiator?
I was thinking of adding some AlumaSeal powdered aluminum sealant to the system but not sure if this is a good idea.

Any suggestions?
Thanks in advance.