The Cummins/Onan 4BT3.9 engine line groups 5 variant designations. Parts and fitment are pooled here so a cross-reference found on one variant surfaces for the whole family.
| Part # | Description | Category |
|---|---|---|
| 982-0200 | Air Filter | Air filter |
| AN500T0083 | ALTERNATOR | Alternator |
| 328876800 | Belt, V-Grooved | Belt |
| 3824469 | fuel pump gear puller | Fuel pump |
| DM-3801371 | Gasket Set - 4BT 3.9 | Gasket |
| FP-4B39PREM | 4B/4BT3.9 In-Frame Kit w/upper gasket set & oil pan gasket | Gasket |
| FP-4B39PREML | 4B/4BT3.9 In-Frame Kit w/upper gasket set & oil pan gasket (late) | Gasket |
| FP-IFK4B39PREM | 4B/4BT3.9 In-Frame Kit w/upper gasket set & oil pan gasket | Gasket |
| FP-IFK4B39PREML | 4B/4BT3.9 In-Frame Kit w/upper gasket set & oil pan gasket (late) | Gasket |
| DM-3805455 | Oil Cooler Hose - 4BT 3.9 | Hose |
| 3822509 | Injection Pump Bore Brush Service Tool | Injector |
| 3823276 | injector bore brush | Injector |
| DM-3029550 | Fuel Injector - 4BT 3.9 | Injector |
| 0332-3925-02 | Jumper-Terminal | Jumper terminal |
| 0332-3943-02 | Jumper-Terminal | Jumper terminal |
| 0249-0814 | Relay 2P Base | Service part / kit |
| 0332-3926 | Terminal Block (End Stop) | Service part / kit |
| 0332-3927-02 | Terminal Block (End Plate) | Service part / kit |
| 300-2810 | Board - Engine Monitor (All) (Includes Fuses) | Service part / kit |
| 305-0823 | # Model MX321 | Service part / kit |
| 3377259 | bosch timing tool (ve) | Service part / kit |
| 965-0520 | Cooling Fan | Service part / kit |
| DM-3802010 | Main Bearing Set Standard - 4BT 3.9, 6BT 5.9, 6CT 8.3 | Service part / kit |
| DM-3004242 | Fuel Transfer Pump - 4BT 3.9 | Pump |
| DM-3805403 | Water Pump - 4BT 3.9, 6BT 5.9 | Pump |
| DM-3807788 | Oil Pump - 4BT 3.9 | Pump |
| 0307-3047 | Relay (24V) | Relay 24v |
| AN500T0013 | STARTER MOTOR | Starter |
| 0332-3923-02 | Terminal Block | Terminal block |
| 0332-4036-02 | Terminal Block (Earth) | Terminal block |
| DM-3015282 | Thermostat 180F - 4BT 3.9, 6BT 5.9 | Thermostat |
Parts cataloged across all variants of this engine family — verify the exact part fits your specific variant and serial number before ordering.