Cummins/Onan JWC4-10S-3 — Draining the Cooling System
Maintenance
For the Cummins/Onan JWC4-10S-3, from the Cummins/Onan service manual.
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Procedure
- Open drain cock at lower right hand corner of radiator, just under water outlet.
- Open drain cock at lower left front corner of cylinder block.
- Save anti-freeze or rust inhibitor drained from system in a clean container for re-use.
Tools required
- Wrenches Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Cooling system capacity 15-1/2 quarts
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.