John Deere 9.0 L Diesel Engines — Check and Service Cooling System
Maintenance
For the John Deere 9.0 L Diesel Engines, from the John Deere service manual.
Applies to: John Deere 6090H engine
Before you start
- Do not drain coolant until the coolant temperature is below operating temperature. Always loosen coolant pump drain valve and block drain valve slowly to relieve any excess pressure.
- Both coolant pump drain valve and block drain valve must be opened to completely drain the engine.
- Air must be expelled from cooling system when system is refilled.
Procedure
- Remove trash that has accumulated on or near radiator.
- Visually inspect entire cooling system and all components for leaks or damage; repair or replace as necessary.
- Remove the foam filter from the weep hole located on the side of timing gear cover and discard filter.
- Insert a heavy gauge wire deep into weep hole to make sure hole is open.
- Install new foam filter flush with timing gear cover.
- Remove and check thermostat(s).
- Drain and flush cooling system.
- Fill cooling system with coolant.
- Run engine until it reaches operating temperature; check entire cooling system for leaks.
- After engine cools, check coolant level; level should be even with bottom of radiator filler neck.
- Check system for holding pressure.
Tools required
- heavy gauge wire Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Full service-parts list: John Deere 6090H engine →
Source: John Deere 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.