Cooling System Components, Removing and Installing Audi TT 8N

Note. The cooling system is under pressure when the engine is warm. If necessary reduce pressure before repair. Secure all hose connections using hose clamps appropriate for the model type VAG 1921 hose clip pliers are recommended for installing spring-type clamps. Always replace gaskets, seals and O-rings. The arrows which are marked on coolant lines and hoses must face each other.

Scheme 204

Coolant hose connection diagram

1 - Radiator

1. Removing and installing. Refer to «Radiator, removing and installing»(ref-276269-S03116130422008010300000)
2. After replacing, fill with new coolant

2 - Non-return valve

3 - After-run coolant pump -V51

1. Removing and installing. Refer to «After-run coolant pump -V51-, removing and installing»(ref-276269-S30165700312008010300000)

4 - Oil cooler

1. After replacing, fill with new coolant

5 - Coolant pump

1. Removing and installing. Refer to «Coolant pump, removing and installing»(ref-276269-S16042608922008010300000)

6 - Cylinder head/cylinder block

1. After replacing, fill with new coolant

7 - Expansion tank

8 - Filler cap for expansion tank

1. With pressure relief valve
2. Checking pressure relief valve. Refer to «Pressure relief valve in filler cap, checking»(ref-276269-S14089392272008021500000)

9 - Throttle valve control module -J338

10 - Heat exchanger

1. After replacing, fill with new coolant

11 - Thermostat

1. Removing and installing. Refer to «Thermostat housing, removing and installing»(ref-276269-S29370771572008010300000)
2. Checking. Refer to «Thermostat housing, checking»(ref-276269-S34979774042008010300000)

12 - Non-return valve

13 - ATF cooler

1. After replacing, fill with new coolant

14 - Auxiliary radiator

1. After replacing, fill with new coolant

Scheme 205

Special tools and equipment required

1. Adapter for cooling system tester V.A.G 1274/8
2. Drip tray V.A.G 1306
3. Hose clamp pliers V.A.G 1921
4. Cooling system charge unit VAS 6096 with VAS 6096/1

1. Refractometer T10007

Draining

Note. Collect drained coolant in a clean container for re-use or disposal.

1. Open filler cap on expansion tank.

1. Remove fasteners -1...3- and remove center sound insulation.
2. Place drip tray V.A.G 1306 under engine.

1. Turn drain plug (arrow) on radiator counter-clockwise and, if necessary, fit a drain hose to connection.

1. In addition, remove lower coolant hose at After-run coolant pump -V51- (arrow) and drain remaining coolant.

Filling

Note. The cooling system must be filled year round with a mixture of water and frost and corrosion protection additives. Only use coolant additive Plus G 012 A8F A1 (also designated as "G12+") meeting specification TL VW 774 F. Other coolant additives could seriously impair in particular the anticorrosion properties. The resulting damage could lead to loss of coolant and consequently to serious engine damage. Coolant additive "G12+" may be mixed with additives "G11" and "G12". "G12+" and coolant additives marked with "Meets specification TL VW 774 F" prevent frost and corrosion damage as well as stop scale from forming. They also raise the boiling point. Therefore, cooling system must be filled year round with the correct antifreeze and corrosion protection additives. A higher boiling point improves engine reliability under heavy load particularly in countries with tropical climates. Frost protection must be ensured to about -25° C (about -35° C in countries with arctic climates). The coolant concentration must not be reduced by adding water even in warmer seasons and in warmer countries. The coolant additive portion must be at least 40%. If greater frost protection is required in very cold climates, the amount of "G12+" can be increased, but only up to 60% (this gives frost protection to about -40° C). If the antifreeze percentage exceeds 60%, frost protection decreases again and cooling efficiency is also impaired. Only use clean drinking water for mixing coolant. If the radiator, heat exchanger, cylinder head, cylinder head gasket or cylinder block have been replaced, do not re-use the old coolant. Contaminated or dirty coolant must not be used again. To check frost protection level of coolant additive "G12+" use refractometer T10007.

1. Close drain plug (arrow).

1. Connect coolant hose to After-run coolant pump -V51- (arrow).

Scheme 206

1. Fill reservoir VAS 6096/1 with at least 8 liters of premixed coolant (based on recommended ratio)

1. "G12+" (40%) and water (60%) for frost protection to 25° C
2. "G12+" (50%) and water (50%) for frost protection to 35° C
3. "G12+" (60%) and water (40%) for frost protection to 40° C

1. Screw adapter for cooling system tester V.A.G 1274/8 onto coolant expansion tank.
2. Mount cooling system charge unit VAS 6096 onto adapter V.A.G 1274/8.
3. Feed vent hose -1- into a small container -2-. (The vented air draws along a small amount of coolant, which should be collected.)
4. Close both valves -A- and -B- (turn lever perpendicular to direction of flow).

1. Connect hose -3- to compressed air.

1. Pressure: 6...10 bar

1. Open valve -B- (turn lever in direction of flow).

The suction jet pump generates a vacuum in the cooling system.

1. Needle on gauge must move into green zone

Scheme 207

1. Also briefly open valve -A- (turn lever in direction of flow) so that hose on coolant expansion tank, VAS 6096/1, can fill with coolant.
2. Close valve -A- again.
3. Leave valve -B- open for another 2 minutes.

1. Suction jet pump will continue generating a vacuum in the cooling system.
2. Needle on gauge must remain in green zone.

1. Close valve -B-.

1. Needle on gauge must stop in green zone. Vacuum level in cooling system is then sufficient for subsequent filling.

If the needle does not reach the green area, repeat the process.

If the vacuum level drops, there is a leak in the cooling system.

1. Disconnect compressed air hose.
2. Open valve -A-.

The vacuum in the cooling system causes the coolant to be drawn out of the cooling system charge unit VAS 6096/1; the cooling system is then filled.

Scheme 208

1. Check coolant level and top up coolant as far as MAX mark.
2. Start engine, run for maximum of 2 minutes at approx. 1500 RPM and fill coolant up to overflow hole on expansion tank.
3. Close expansion tank.
4. Run engine until coolant fan starts.

1. Check coolant level and top up if necessary.

1. When engine is at normal operating temperature, coolant level must be at MAX mark. When engine is cold coolant level must be between MIN and MAX marks.

1. Switch engine off.

Scheme 209

Special tools and equipment required

1. Support bracket 10-222 A
2. Shackle 10-222 A/12
3. Drip tray V.A.G 1306
4. Coolant pump spanner V.A.G 1590

1. Hose clamp pliers V.A.G 1921
2. Bolt M8 x 40

Removing

1. Open filler cap on coolant expansion tank.

1. Loosen hose clamp -1- and disconnect air hose at Throttle valve control module -J338-.
2. Move electrical wire (arrow) clear.

Note. Hose clamp -2- remains attached.

1. To remove fasteners -1- at lock carrier, press pin -2- in approx. 4 mm (do not push in completely). Then pull fastener out upward.

1. Remove covers (right side) -1- and -2- at lock carrier and above coolant expansion tank (arrows).

Note. Before removing, mark direction of rotation of poly V-belt with chalk or a felt-tipped pen. If the belt runs in the opposite direction when it is re-installed, breakage may result.

1. To release tension of poly V-belt, screw an M8 x 40 bolt into bore on tensioning element.

Scheme 210

1. Attach shackle 10-222 A/12 to right rear engine lifting eye.
2. Place support bracket 10-222 A on surface of panel flange; spindle faces forward.
3. Attach spindle hook to shackle.
4. Pretension spindle slightly.

1. Remove securing bolt (arrow) for power steering reservoir.

1. Loosen bolts (arrows) of assembly mounting (left side) on engine.

1. Remove fasteners -1...3- and remove center sound insulation.

1. Remove right sound insulation (arrows).
2. Place drip tray V.A.G 1306 under engine.

1. Turn drain plug (arrow) on radiator counter-clockwise and, if necessary, install drain hose to connection.

1. In addition, remove lower coolant hose at After-run coolant pump -V51- (arrow) and drain remaining coolant.

1. Remove bolts (arrows -A-) for pendulum support at subframe.

Scheme 211

1. Remove pulley; counterhold using coolant pump spanner V.A.G 1590.

Note. The pulley must not be removed if the engine has been taken out. In this case, the securing bolts for the coolant pump are accessible through the holes of the pulley.

Scheme 212

1. Remove bolts -1- for coolant pump -2-.

1. Lower engine via spindle approx. 65 mm.
2. Swing coolant pump forward and remove.

Installing

Installation is performed in the reverse order. Note the following

Note. Replace the O-ring.

1. Clean and smooth surface for O-ring as required.
2. Moisten new O-ring with coolant "G12+".

1. Install coolant pump -2-.
2. Tighten bolts -1- for coolant pump.
3. Install coolant pump pulley.
4. Install poly V-belt. Refer to «Poly V-belt, removing and installing»(ref-276269-S17467268642008010300000) .

1. Adjust engine mountings. Refer to «Engine mountings, checking and adjusting»(ref-276269-S22031994392008010300000) .

Tightening torques

Scheme 213

1 - O-ring

1. Replace

2 - Retaining clip

3 - Thermostat housing

1. Removing and installing. Refer to «Thermostat housing, removing and installing»(ref-276269-S29370771572008010300000)

4 - Bracket

5 - 10 Nm

6 - Thermostat

1. Removing and installing. Refer to «Thermostat housing, removing and installing»(ref-276269-S29370771572008010300000)
2. Checking. Refer to «Thermostat housing, checking»(ref-276269-S34979774042008010300000)

7 - Connection

8 - Gasket

1. Replace

9 - Engine Coolant Temperature (ECT) sensor -G62

1. With ECT sensor -G2
2. Dissipate cooling system pressure before removal if necessary

10 - Sealing plug

1. Dissipate cooling system pressure before removal if necessary