Didn’t leak at the connection point. The only tough part was pulling off the reservoir when I was done and not having the some fluid spillover that was left in the tip of the funnel between the plug and the radiator connector. I usually just cover the area with paper towels in preparation for this.
https://www.amazon.com/EPAuto-Radiator-Coolant-Filling-Funnel/dp/B01I40ZQWE

