Their supposed "policy" is to suggest replacing the whole thing since the Check Engine light can come on after messing with the solenoid. However, when I spoke with the mechanic directly, he said that he would replace the gasket if it were his and take the risk. $12 part versus a $343 part.... So that's what I did. Because of other issues on the car, I haven't heard if that fixed the leak without causing the Check Engine. I'll know more tomorrow.