Cummins/Onan — Coolant Filter (Corrosion Resistor) Element Change
Maintenance · Water filter / coolant corrosion resistor
From a Cummins/Onan operator's manual covering: 37.5 DEF-515R, 37.5 DEF-53R, 40.0 DEF-15R50, 40.0 DEF-3R50, 45.0 DEF-15R, 45.0 DEF-3R, 45.0 DEF-9XR, DEF-15R, DEF-15R50, DEF-3R50, DEF-515R, DEF-53R…. Check it applies to your exact model before use.
Applies to: Cummins/Onan 45.0 DEF-15R, Ford 2713E engine
Before you start
- Do not use antifreeze with an anti-leak formula; stop-leak element can prevent or retard flow through the filter.
Parts for this job
Part numbers from the service-parts list for Cummins/Onan 45.0 DEF-15R. Verify against your serial number before ordering; some links are affiliate links.
Procedure
- Clean filter body and surrounding area; close coolant inlet and outlet shutoff valves.
- Remove drain plug from bottom of filter body and drain coolant.
- Remove capscrews attaching filter cover; remove cover.
- Lift upper plate and filter element out; discard filter element.
- Remove lower corrosion resistor plate and spring; inspect and clean plate, replace if thin, pliable or holed.
- Remove and clean sump plate; clean sump area.
- Install sump plate, spring, lower corrosion resistor plate, and new filter element.
- Install cover with gasket; replace drain plug and open shutoff valves.
Specs & values
- Service each 300 to 500 hour interval
- Initially change PAF (borate) element after 150 hours
Full service-parts list: Cummins/Onan 45.0 DEF-15R →
Source: Cummins/Onan operator'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.