Why is my 3/8" coupler leaking from the end?
If your QD connection is spraying water out the sides and is leaking, your o-ring is likely damaged or missing. Check inside the coupler on the end of your hose and see if the o-ring is still in there or if its damaged.
You can get the o-ring out to inspect or replace it with a small flathead screwdriver or pick. To reinstall, push it in with your finger as close as you can, and then use the screwdriver or pick again to properly seat the o-ring into place.
Here is the o-ring you need for the 3/8” coupler: