Ford CSG-850 / WSG-858 — Thermostat Replacement
Maintenance · Cooling system thermostat
For the Ford CSG-850 / WSG-858, from the Ford service manual.
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Before you start
- Do not attempt to repair the thermostat; replace it if not operating properly
Procedure
- Drain the cooling system so the coolant level is below the thermostat.
- Remove the water outlet housing retaining bolts; remove thermostat and gasket.
- Clean gasket surfaces; coat a new water outlet housing gasket with water-resistant sealer.
- Install thermostat with copper pellet or element toward engine and flange in recess.
- Position water outlet housing; torque retaining bolts to specifications.
- Fill and bleed the cooling system; run engine to normal temperature and check for leaks.
Tools required
- Wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Thermostat low temperature opens 157°-164°F; high temperature opens 188°-195°F
Source: Ford 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.