Audi Workshop Service and Repair Manuals

Removing, installing and checking thermostat

Special tools and workshop equipment required

t	Locking pin -T40011-

t	Socket (22 mm) -3078-

t	Locking pin -3242-

t	Diesel injection pump locking pin -3359-

t	Locking fluid → Parts catalogue

Removing –  Drain off coolant → Chapter. –  Remove front bumper cover → General body repairs, exterior; Rep. Gr.63. –  Move lock carrier into its service position → General body repairs, exterior; Rep. Gr.50. –  Remove poly V-belt for power steering pump, alternator and viscous fan → Chapter

–  Remove securing bolts -arrows- for toothed belt cover (rear right). –  Turn the crankshaft to TDC.   Caution The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise).   Note Turn over the engine at the central bolt on the crankshaft.

–  Rotate crankshaft until the smaller drilling -1- of the two drillings on the vibration damper is positioned at the top. –  Lock injection pump sprocket with locking pin -3359-. l  It must be possible to insert locking pin into drilling on injection pump; rotate crankshaft slightly in both directions if necessary.

–  Unscrew plug for TDC marking from cylinder block.   Note There is a TDC drilling in the crankshaft directly behind the plug (it is possible to feel the hole).   WARNING To avoid any risk of injury, do not rotate the crankshaft while feeling for the TDC hole with your finger. –  Screw locking pin -3242- into threaded hole where plug has been removed, and tighten. –  Remove locking pin -3359- from vibration damper.

–  Remove vibration damper on injection pump sprocket (bolts -1-).   Caution Do NOT loosen nut -2- for injection pump sprocket. Otherwise this would alter the basic setting of the injection pump. The setting cannot be re-adjusted with workshop equipment.   Note

Before removing, mark rotation direction of toothed belt with chalk or felt-tipped pen. If the belt runs in the opposite direction when it is refitted, this can cause breakage. –  Slacken toothed belt tensioner and take off toothed belt for injection pump.

–  Unbolt drive sprocket -1- for injection pump from camshaft sprocket -arrows-.

–  Remove 8 bolts -1- and detach vibration damper.   Note Central bolt does not have to be loosened when removing vibration damper.

–  Unbolt bottom section of toothed belt cover -4-. –  Remove viscous fan pulley. –  Remove bolts -1 ... 3- and detach bracket for viscous fan with idler rollers.

–  Turn toothed belt tensioning roller in direction of -arrow- using an 8 mm Allen key until tensioning lever of tensioner is compressed far enough to allow locking pin -T40011- to be inserted into the hole and the plunger.   Note The toothed belt tensioner is oil-damped and can therefore only be compressed slowly by applying constant pressure.

–  Pull toothed belt forwards slightly on tensioning roller -arrow-.   Caution Timing must be re-adjusted if toothed belt has slipped off tensioning roller → Anchor. –  Detach coolant hose from thermostat housing. –  Remove bolts -1 ... 3- and detach thermostat housing. –  Remove O-ring and thermostat.

Installing   Note Renew O-rings. –  Install thermostat (note installation position): l  Vent valve -arrow- faces upwards. l  Seal facing housing –  Install thermostat housing.

–  Apply locking fluid to bolts -2- and -3- before installing.   Caution Timing must be re-adjusted if toothed belt has slipped off tensioning roller → Anchor.

–  Push toothed belt to rear. –  Slacken belt tensioner using 8 mm Allen key -arrow- and pull out locking pin -T40011-.

–  Pre-tension toothed belt to 15 Nm by turning with torque wrench in direction of -arrow-.

–  Install bracket for viscous fan: 1 -  45 Nm 2 -  10 Nm 3 -  22 Nm 4 -  10 Nm –  Install viscous fan pulley.

–  Lock injection pump sprocket with diesel injection pump locking pin -3359-.

–  Fit drive sprocket for injection pump -1- so that it is aligned centrally in elongated holes. –  Tighten drive sprocket -arrows- until it is still just possible to turn it on the camshaft sprocket. –  Fit toothed belt for injection pump on sprockets. Pay attention to the direction of rotation as marked upon removal.

–  Tension toothed belt. To do so, turn Allen key anti-clockwise in direction of -arrow- until marks -1- coincide. –  Then tighten securing nut using socket (22 mm) -3078-.   Note Depending on version, pointer -1- may have no tip. –  Tighten bolts at camshaft sprocket. –  Remove diesel injection pump locking pin -3359-. –  Remove locking pin -3242-. –  Screw plug for the TDC mark into cylinder block with a new seal.

–  Check tension of toothed belt for injection pump. l  Marks -1- and -2- must be opposite one another.

–  Fit vibration damper on injection pump sprocket (bolts -1-).

–  Install vibration damper. In doing so, pay attention to locking lug -arrow- on toothed belt sprocket. Remaining installation steps are carried out in reverse sequence; note the following: –  Install poly V-belt for power steering pump, alternator and viscous fan. → Anchor –  Install viscous fan → Chapter. –  Install lock carrier with attachments → General body repairs, exterior; Rep. Gr.50. –  Install front bumper cover → General body repairs, exterior; Rep. Gr.63. –  Fill cooling system → Anchor. –  Dynamically check and adjust commencement of injection → TDI injection and glow plug system (6-cyl.); Rep. Gr.23. Tightening torques

Component			Nm
Thermostat housing to cylinder block			10 → Note
Viscous fan pulley to hub			10
Tensioning roller for injection-pump toothed belt to bracket for viscous fan			36
Drive sprocket for injection pump to camshaft			22
Screw plug in cylinder block		M6	10
		M18	35
Vibration damper to injection pump sprocket			22
Toothed belt cover (rear) to	Cylinder head		10
	Injection pump		10
Vibration damper to crankshaft sprocket			22

1)  Install using locking fluid; locking fluid → Parts catalogue. Checking thermostat –  Heat thermostat in water bath.

Starts to open	Fully open	Opening travel
approx. 87 °C	approx. 102 °C → Note	at least 8 mm

2)  Cannot be tested