I know that a subject line of "radiator clamps and hoses" sounds like Volvo 101, but I am having a very frustrating problem. Where the top radiator hose connects to the radiator there is a very small but persistent leak. Removed that clamp and tried some spare clamps that were just lying around but there is still a leak. I don't want to torque the clamp down too hard for fear that the plastic part of the radiator will crack. BTW, that plastic part on the radiator where the hose connects looks fine. Any suggestions? Thanks.