Caterpillar 3406 — Cooling System Clean/Flush and Thermostat Replacement

Maintenance

For the Caterpillar 3406, from the Caterpillar owner's manual.

Applies to: Caterpillar 3406

Procedure

1. Stop engine, allow to cool, tag out starting system
2. Loosen vent cap slowly to relieve pressure and drain system
3. Disconnect hose from thermostat housing, remove bolts and housing
4. Remove gasket, thermostat, and seal from housing
5. Refill with clean water plus 6-10% Fast Acting-Type cleaner, or 1 L per 15 L water for Standard-Type
6. Run engine to circulate, then stop, cool, and drain repeating flush until clear
7. Install new seal, thermostat, and gasket; reinstall housing and connections
8. Fill with water/Caterpillar Antifreeze mixture per Refill Capacities chart
9. Run engine with vent cap loosened until thermostats open and level stabilizes
10. Top off coolant to within 13 mm (1/2 in) of fill tube bottom

Full service-parts list: Caterpillar 3406 →

Source: Caterpillar 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.

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