Thermostat: Service and Repair

11 53 000 Removing and installing/replacing coolant thermostat (N51)







WARNING:
Risk of scalding.
Only perform these tasks on an engine that has cooled down.
Danger of injury.
Risk of slipping due to coolant on the floor.







Recycling:
Catch and dispose of drained coolant.
Observe country-specific waste disposal regulations.

IMPORTANT:
Read and comply with General Notes.
Protect plug connections against coolant and contamination.
Cover plug connections with suitable materials.







Necessary preliminary tasks:
- Remove front underbody protection.
- Place oil drip tray for coolant under engine compartment.







NOTE: Illustration shows coolant thermostat removed.

Disconnect coolant hoses (arrows) on the thermostat (1) with clamping tongs.







Release hose clamp (1) and detach coolant hose.
Release hose clamp (2) and detach coolant hose.
Unlock and detach coolant hose (3).
Unlock and detach coolant hose (4).
Disconnect plug connection (5).
Release screws (6).
Tightening torque: 11 53 1AZ.
Remove coolant thermostat (7).

NOTE: Illustration shows coolant thermostat removed.







Assemble engine.
Fill the cooling system.
Check function of cooling system.

Installation note:
Check coolant hoses for cracks and damage.
Renew coolant hoses as required.

Recommendation:
On vehicles older than five years, renew coolant hoses.