[Elvis74]

By the way, last weekend we went out for riding and a friends EC300 with S3 cylinder head was loosing cooling water. After checking all hoses, gaskets and other things, we saw that the water came out of the cylinder head where the spark plug is. We opened the head and noticed that the O-Ring was very hard and not sealed any more! The strange think, the S3 head was mounted for only 8 month!
Everybody who is running the S3 head, put a extra I-ring in your pocket or check it from time to time, looks like they use the wrong material.