Cummins/Onan GTA38 / GTA50 — Water Pump - Remove and Install
Repair & overhaul · Cooling system
For the Cummins/Onan GTA38 / GTA50, from the Cummins/Onan owner's manual.
Applies to: Cummins/Onan GTA38 engine, Cummins/Onan GTA50 engine
Before you start
- Component weighs 23 kg [50 lb] or more; use a hoist.
Procedure
- Drain cooling system; remove the coolant by-pass tube.
- Disconnect lower radiator/heat exchanger hose from pump inlet.
- Remove water pump inlet housing cap-screws and support bracket.
- Remove cap-screws holding pump to water pump drive (use hoist).
- Remove pump and coupling; remove plate; discard o-ring and gasket.
- Install o-ring in adapter plate groove; lubricate with vegetable oil.
- Install adapter plate, spline coupling and gasket on pump.
- Position pump on drive; align spline coupling with drive splines.
- Install cap-screws; tighten pump-to-drive to 60 Nm [45 ft-lb].
- Tighten adapter plate cap-screws to 40 Nm [30 ft-lb].
- Install inlet housing with o-ring; tighten to 40 Nm [30 ft-lb].
- Tighten bracket-to-hand-hole-cover cap-screws to 60 Nm [45 ft-lb].
- Close drain-cocks; replace coolant filters; fill cooling system.
- Operate to 70C [160F] and check for leaks.
Tools required
- Hoist Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Pump-to-drive 60 Nm [45 ft-lb]
- Adapter plate 40 Nm [30 ft-lb]
- Bracket 60 Nm [45 ft-lb]
Source: Cummins/Onan owner's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.