Audi Workshop Service and Repair Manuals

Removing, installing and checking thermostat Special tools and workshop equipment required

t  2-hole pin wrench -3212-

t  Locking pin -T40011-

Removing –  Remove front bumper → Rep. Gr.63. –  Move lock carrier to service position → Rep. Gr.50. –  Drain off coolant → Chapter. –  Remove poly V-belt → Chapter. –  Unscrew bolt -arrow- and remove tensioner for poly V-belt.

Vehicles with secondary air system: –  Disconnect hose -arrow- from secondary air connecting pipe.

All models: –  Provide support for power steering pump pulley using two-hole pin wrench -3212- and unscrew pulley -arrows-. –  Unscrew radiator cowl for viscous fan. –  Remove right toothed belt cover (2 sections). Vehicles with “engine generation III”: –  Remove vibration damper → Chapter. –  Remove toothed belt cover (bottom). All models: –  Disconnect coolant hoses at thermostat housing.   Note

The toothed belt tensioner is oil-damped and can therefore only be compressed slowly by applying constant pressure. –  Turn toothed belt tensioning roller -1- clockwise in direction of -arrow- using an 8 mm Allen key until tensioning lever -2- compresses tensioner -3- far enough for the pressure piston to be locked with locking pin -T40011-. –  Insert locking pin -T40011- and release toothed belt tensioning roller.

–  Pull toothed belt forwards slightly on tensioning roller and right camshaft sprocket -arrows-, but do not pull off completely.   Caution Timing must be re-adjusted if toothed belt has slipped off tensioning roller → Anchor.

–  Detach thermostat housing -arrows-.   Note Illustration shows thermostat housing with toothed belt detached. –  Remove O-ring and thermostat.

Installing Installation is carried out in the reverse order; note the following:   Note Renew O-ring. –  Before installing, clean and smoothen sealing surface for O-ring. –  Install thermostat. Fitting position: l  Vent valve -arrow- faces upwards. l  Seal facing housing –  Install thermostat housing.   Caution Timing must be re-adjusted if toothed belt has slipped off tensioning roller → Anchor. Follow all instructions for removing and installing toothed belt → Chapter.

–  Using an 8 mm Allen key, turn toothed belt tensioning roller -1- clockwise in direction of -arrow- until the locking pin -T40011- can be removed. Proceed as follows to pre-tension tensioning roller before first starting engine: –  Apply torque wrench to hexagon socket of tensioning roller. –  Pre-tension tensioning roller by applying a torque of 15 Nm. Vehicles with “engine generation III”: –  Install vibration damper → Chapter. All models: –  Install poly V-belt → Anchor. –  Fill cooling system → Anchor. Tightening torque

Component			Nm
Thermostat housing to cylinder block			10

Checking thermostat –  Heat up the removed thermostat in hot water.

Starts to open	Fully open	Opening travel
approx. 87 °C	approx. 102 °C 1)	at least 8 mm
l  1) Cannot be tested.