|I know this is a slightly old thread, but this is the only one that I could find that has my problem. before I even found this thread, I knew what my problem was and I even did what FaelinGL told the OP to do. I have already replaced both of the o rings and it fixed the leak for 3 days. today, I noticed a puddle under the car and I refilled the coolant. I have no reason to believe that the leak is coming from somewhere that is not one of these o rings. what I don't understand is why would this work for 3 days and then start to leak again? any insight?