Cummins/Onan — Draining the Fuel Filter
Maintenance · Fuel system
From a Cummins/Onan owner's manual — check it applies to your exact model before use.
Applies to: Cummins/Onan MDDC, John Deere 4045TFM engine, John Deere 6068TFM engine
Before you start
- Diesel fuel is combustible.
- Engine components can be hot.
Parts for this job
- 149-2106 Fuel filter — Cummins/Onan MDDC Amazon eBay $34.99 NAPA $61.61 KuduParts $68.00
- DQ24057 Fuel filter — John Deere 4045TFM engine Amazon eBay $19.49
Part numbers from the service-parts lists for Cummins/Onan MDDC, John Deere 4045TFM engine. Verify against your serial number before ordering; some links are affiliate links.
Procedure
- Disconnect negative battery cable with insulated wrench.
- Open the front access door.
- Disconnect the water sensor connector.
- Loosen vent and drain screws; drain water and sediment into a container (about 1/2 cup or 120 ml).
- Close drain screws, tighten vent, reconnect water sensor.
- Replace front access door and reconnect negative battery cable.
- Dispose of drain-off per local regulations.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- About 1/2 cup or 120 ml drained
Full service-parts list: Cummins/Onan MDDC →, John Deere 4045TFM engine →
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.