Well the header says it all. My old astra ( 96) had the same problem when it reached about 50,000 miles. This one is only a couple of years old and at
35,000 miles is diaspaying the same problem. It had a touch of grease in when I bought it which was a clue I guess. Only happens when ambient temp inside car gets above about 25c. Is this common and is there an easy solution ?