Removing and Installing/Replacing Coolant Thermostat

11 53 000 Removing and installing/replacing coolant thermostat (N55)

Special tools required:







WARNING:
Risk of scalding.
Only perform this work after engine has cooled down.
Danger of injury.
Use only special tool 17 2 050 to lock and release spring strap.







Recycling
Observe country-specific waste disposal regulations.
Catch and dispose of drained coolant in a suitable container.







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 collecting vessel for coolant under engine compartment.







Disconnect coolant hoses (arrows) from thermostat using grips.







Unlock and detach coolant hose (1).

WARNING: Danger of injury. Only lock and unlock spring strap (2) with special tool 17 2 050.

Lock hose clamp (2) on coolant thermostat with special tool 17 2 052.
Detach coolant hose from thermostat.
Unlock and detach coolant hose (3).
Release hose clamp (4) and detach coolant hose.
Release screw (5) and remove coolant thermostat.

Installation note:
Unlock spring band clamp (2) with special tool 17 2 051.

Assemble engine.
Fill cooling system.
Observe filling capacities.

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







Recommendation:
On vehicles older than five years, renew coolant hoses.
Check function of cooling system.