Karcher 4.551-159.3 Cylinder Head Only For Model K2 K3 Pressure Washers Power Tool Centre Proudly Offers Genuine Karcher 4.551-159.3 Cylinder Head Only For Model K2 K3 Pressure Washers Karcher Cylinder Head 4.551-159.3 This is a genuine spare part to fit select models of Karcher pressure washers. If your Karcher isn't reaching high pressure, and you've noticed the trigger is "pulsing" this could mean you need to replace the cylinder head. If this is the case with your machine than this high quality cylinder head is the perfect replacement part to get your pressure washer back to its best. For Model K2 Premium Full Control Home K2 Basic Car K2 Compact K2 Compact Car Home K2 Power Control K3 Home K3 Power Control K2 Compact GB (2017) We Are An .