I wouldn't... The pressure used (if not very low) could damage any fittings along the 'lines' IF BLOCKED. Best to carefully 'back flush' with very low pressure below the pump pressure output WITH one or more hoses 'open' so that any little flapper 'valves' that might be in the system (because if there is one and you reverse flow, you might damage it). These little washer fluid hoses aren't designed to hold any pressure since the one end is always open to atmosphere. Anyway, sometimes going slow but sure guarantees a better result in general.


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