These are the rings that fit inbetween the heat exchanger and the head and must be replaced every time the heat exchanger is removed. please make sure that the old rings are carefully removed by pinching them out rather than using a chisel that could damage the sealing surface. never stack the rings! one per cylinder! 1.7 rings have a slightly smaller interior diameter than the 2.0 variety. Four required.
Known as: sealing ring