Zx55 Water Pump Explained: A UK Buyer's Guide

If a ZX55 starts running hot on a UK groundworks job, the water pump is one of the first cooling parts worth checking. This listing is the aluminium Isuzu 4LE1 coolant pump supplied to 8972541481, with a housing gasket and smaller round seal in the box.

What the ZX55 water pump is doing

It is a belt-driven pump that moves coolant through the 4LE1 and out to the radiator. Compact excavators spend long hours digging with little ram-air, so a leaking seal or a noisy bearing shows up as temperature climb and wet staining on the housing.

Which machines take this pump

ZX55, ZX55UR, E55 and EX55 machines that run an Isuzu 4LE1 take this unit when the old pump is stamped 8972541481 or 8-94140341-0. Check that stamp before you order. The pulley hub has four fixing holes and the hose necks follow the 4LE1 layout.

Failure signs on site

Weep-hole leaks, play in the pulley, a grind from the front of the engine, or a gauge that climbs under load after belt and coolant level are confirmed. Leave a failed pump and the 4LE1 overheats on the next loaded hour.

Fitting this aluminium pump

Cold engine, battery disconnected, drain the coolant, strip belt, fan and hoses, clean the block face, fit the supplied gaskets, and tighten the pump-to-block bolts to 1.9–2.9 kg·m (14–21 lbf·ft). Reuse the original bolts. Refill with the coolant the machine maker specifies, bleed, and check for leaks.

See the Isuzu 4LE1 Water Pump 8972541481 for the aluminium housing, packing size and the gasket set in the box.