Mercury - Water Pump Gasket Quicksilver Series Composite Fiber 858524. Overview. There is a certain comfort that comes from knowing your cooling system is sealed up tight. Anyone who's ever watched engine temps climb a little higher than they'd like knows that uneasy feeling in their gut. A simple gasket may not look like much in your hand, but out on the water, it's one of those quiet heroes that keeps everything steady. The Quicksilver Water Pump Gasket 858524 is the kind of part you trust bec