UK made. Large impeller higher capacity water pump with a high quality die cast body.
Fitted with a PPS, glass filled plastic impeller as used by Aston Martin and Jaguar. It reduces weight on the bearing loading and has a triple lip seal giving a better controlled flow rate through the rev range. This pump is about 130 grams lighter and has the rolled edge gasket facing evolved by Rover for better sealing. Tested with coolant pumping at 10,000 rpm with no detriment to the PPS impeller this larger impeller pump moved more coolant than the original early GWP132 standard pump.
GWP134 has the by-pass hose take off. GWP187 does not have a bypass. These water pumps have a much larger impeller that protrudes into the block very slightly more than 1/2"(14.03mm).
This water pump will fit all 1275cc blocks and all small bore blocks, with the exception of early 850/997cc units. These early blocks will need an amount of modification, relieving corrosion and slight material from the liner wall and impeller if required should enable clearance, try spinning pump loosely fitted without gasket for clearance. The high capacity water pump helps to reduce cavitation in the water jacket, particularly at high RPM, as well as circulating a greater volume of coolant.