Cummins/Onan — Remove and Install Water Pump (H/NH Series)
Repair & overhaul
From a Cummins/Onan service manual covering: V12 Series, V6-140, V6-200, V6-VAL, V6-VIM, V8-185, V8-265, V8-350, V8-VALE, V8-VINE, VT12, VT8-430. Check it applies to your exact model before use.
Applies to: Cummins/Onan V12 Series
Before you start
- Avoid stretching belts; loosen adjusting screw until belts go into position easily.
Procedure
- Remove fan from fan pulley.
- Loosen adjusting screw and remove fan hub, pulley and belts from mounting bracket.
- Drain cooling system.
- Loosen capscrews holding fan bracket support to rocker housing.
- Loosen capscrews in the water pump clamp ring.
- Using a screwdriver in pump housing holes, turn water pump to lowest point of eccentric to loosen belt.
- Remove water pump belt, fan bracket and support.
- Remove water pump from block.
- Installation: place clamp ring and gasket on pump.
- Assemble drive belt on water pump pulley and drive pulley.
- Turn pump to low point of eccentric and install in block; secure loosely.
- Turn pump counter-clockwise on eccentric to tighten belt.
- Tighten capscrews in clamp ring.
- Secure fan bracket support to rocker housing.
Tools required
- Large screwdriver Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Belt tension per Page 2-21
Full service-parts list: Cummins/Onan V12 Series →
Source: Cummins/Onan service 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.