The expansion tank takes the place of a bleed valve. There is a drain in the block as well as the radiator. Do a search; Gilly described the procedure in detail way back when.

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Lenny

There are only three sports: bullfighting, motor racing and mountaineering; all the rest are merely games. --Ernest Hemingway

'10 GL550/'04 BMW 545/'99 BMW 323/'98 ML320/'87 VW GTI (race)