Q: Why does the oil cooler line keep coming out of the radiator in my 2002 Chevrolet S10

Hi there. These couplings that hold the line into the radiator are very temperamental. If the clip is not installed exactly how it should then the line will continue to pop off. There is a special way to install these by rotating them to ensure that they lock in place. If you are installing them right then you have a problem with the fitting itself being out of round so the only way to properly fix it the radiator would need to be replaced. If you want to have this repaired, consider YourMechanic, as a certified mechanic can come to you to [repair this cooler leak] https://www.yourmechanic.com/services/oil-fluid-leak-inspection