Leaf spring
Chain tensioner
Oil pump

Crankshaft chain sprocket,
31 teeth

Chain sprocket, 32 teeth
Chain sprocket shield to reduce
splash loss

Guide rail

Suction pipe with integrated oil
strainer (perforated plate) to
ensure oil supply during dynamic
driving

48

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Oil pump
The fully variable vane pump has a very compact construction. It is bolted onto the crankcase. A metal gasket is necessary to
seal the individual oil passages from one another at the point where the components mate.

Return shut-off valve

Pressure relief valve

Rotary slide valve

Impeller

676_062

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Oil pump: range of operation
Oil temperature in main gallery:
86 °F (30 °C)
Oil temperature in main gallery:
212 °F (100 °C)

676_063

Note

For new vehicles, two-stage oil pressure regulation is only activated after the first 620 mi (1000 km). This compensates for the higher friction when breaking in new parts and is the best way of removing particles of residue
worn off during the break-in process. After installing new components such as the engine/short block, cylinder
head, camshaft housing or turbocharger, activate the “engine run-in” program in the Guided Fault Finding (GFF).
This will ensure that only the high pressure stage is allowed for the next 620 mi (1000 km).

Reference

For further information regarding fully variable oil regulation, please refer to eSelf-Study Program 920173,
The Audi 3.0L V6 TFSI EA839 Engine.
49

Piston cooling
It is not necessary to cool the pistons with oil spray during
every phase of engine operation. When no cooling is
required, Piston Cooling Nozzle Control Valve N522 is
switched to ground by Engine Control Module J623. This
closes off the channel from the main oil gallery to the oil
gallery for the piston cooling jets.

When the oil gallery is closed, the oil pressure dissipates
via the piston cooling jets. Feedback to the ECM is provided
by the signal from Oil Pressure Switch F22. F22 is located
in the oil gallery and opens at pressures between 4.35 8.70 psi (0.3 - 0.6 bar).

Piston cooling jets
676_066

Piston cooling jets: range of operation
Piston cooling is activated based on a characteristic map that considers the variables of engine rpm, engine torque and oil
temperature. For this purpose, Oil Temperature Sensor G8 provides the engine oil temperature value of the main oil gallery.
Piston cooling is only activated at oil temperatures above 50 °F (10 °C).

676_067
50

Sensors and actuators

Oil heat exchanger
Oil Pressure Switch
F22

Oil filter module
Plastic oil filter module
with pressure relief valve in
cover assembly. Connection of
turbocharger oil supply with
integrated non-return valve.
Fully synthetic filter paper

Piston Cooling Nozzle
Control Valve
N522
Oil Temperature Sensor
G8

Oil Pressure Sensor
G10

Oil Level Thermal Sensor
G266

Oil Pressure
Regulation Valve
N428

676_068

Note

Oil Temperature Sensor G8, Oil Pressure Switch F22 and Piston Cooling Nozzle Control Valve N522 are located
under a heat shield.

Oil Temperature Sensor G8
G8 is also located in the inner V of the engine. This NTC
thermistor measures the temperature of the engine oil in
the main oil gallery. The ECM uses the signal primarily as
the input variable for calculating the oil pressure regulation.
In addition, the oil temperature in the main oil gallery
determines whether the piston cooling jets are activated.
For example, at oil temperatures over 248 °F (120 °C), the
piston cooling jets are activated even at low engine speeds.

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51

Oil Level Thermal Sensor G266
The signal from G266 is evaluated by the ECM, which uses
the temperature and oil level values to compute the oil
change interval. The information regarding oil level and oil
temperature is transmitted to the ECM via a PWM signal.
The sensor has a 12 Volt power supply.

676_069

Piston Cooling Nozzle Control Valve N522
This solenoid valve operates on 12 Volt power. To activate
the solenoid valve and close the oil passage for the piston
cooling jets, the ECM switches it to ground. This means that
the valve would be open in the event that it should fail
(failsafe design).

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52

Oil filter and oil-coolant heat exchanger
When the oil exits the oil-coolant heat exchanger, it flows
through a passage in the cylinder block and into the oil
filter module. Once it has been filtered, the oil flows into
the main oil gallery of the engine; from there, it reaches
the appropriate components via corresponding passages.

The engine oil circulated by the oil pump flows first
through the oil heat exchanger, which is installed in the
inner V of the engine and connected to the coolant circuit
on the coolant side.

676_071

The oil-coolant heat exchanger is designed to provide a
high degree of heat transfer. It comprises 19 stacked plates
with plates for turbulent flow (10 oil/9 water), which
provides a high degree of heat transfer. The coolant
circulates via counterflow with a flow rate of up to 63.40 qt
(60l) per minute.

Coolant
outlet

Coolant
inlet

Engine oil
inlet

Engine oil
outlet
Cross-flow of engine oil and coolant through exchanger

676_073

676_072
53

Oil filter module
The oil filter module is made of plastic and is installed in
front of the oil-coolant heat exchanger in the inner V of the
engine. This makes it very easy to replace the oil filter. A
stainless steel heat shield protects the oil filter module by
reflecting the heat that radiates from the turbocharger on
cylinder bank 2.

A bypass valve is installed in the housing cover which
directs the oil past the oil filter should it become clogged.
Two additional valves are installed in the oil filter housing.
The non-return valve prevents oil from flowing from the
turbochargers back into the sump. The oil drain valve opens
when the oil filter cover is unscrewed so that the oil drains
into the sump when the oil filter is exchanged.

Oil filter module

Cover seal
Bypass valve

Oil filter

Oil filter housing

Oil drain valve

Non-return valve

Heat shield

Seal

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54

Oil supply in the cylinder head cover
The main oil gallery in the cylinder block supplies the oil
pressure to the cylinder head cover.
From the main oil gallery, oil is supplied to the camshaft
bearings, the hydraulic compensation elements, the
high-pressure fuel pump and (on cylinder bank 2) the
vacuum pump via branch ports. Oil is supplied to the large
camshaft bearings and the camshaft adjusters via the main
oil gallery of the cylinder head covers.

Main oil gallery, cylinder head
cover

Vacuum pump

High-pressure fuel pump

Hydraulic
compensation
elements
Pressure oil from main oil
gallery

Camshaft adjuster

676_075

55

Drive for ancillaries
The alternator and air conditioner compressor are each
driven by a separate drive belt. Both belt drives are driven
by the vibration damper of the crankshaft.

The belt drives are tensioned by automatic tensioning
devices and are maintenance-free.

Vibration damper
Tensioning roller
(top)
Tensioner for poly
V-belt

Starter-alternator

Air conditioner
compressor

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Tensioning roller
(bottom)

Poly V-belt tensioner for starter-alternator
(belt tensioner/damper)

Idler roller

Poly V-belt tensioner for air conditioner compressor
(belt tensioner/damper)

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56

Vibration damper

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57

Cooling system
System overview
The new V8 engine has a thermal management system
which activates various partial cooling circuits as required
to help the engine, vehicle heating and transmission warm
up quickly.

In addition to providing greater convenience, the main
objective is to reduce fuel consumption and exhaust emissions.

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58

Key:
1. Expansion tank

14. Cylinder head (right-side)

2. Heat exchanger for heater (front)

15. Cylinder block (right-side)

3. Heat exchanger for heater (rear)

16. Cylinder block (left-side)

4. Restrictor

17. Cylinder head (left-side)

5. High Temperature Circuit Coolant Pump V467

18. Engine Temperature Sensor G407

6. ATF cooler
7. Turbocharger, bank 1 (right-side)

19. Coolant pump (mechanical) With cover (standing coolant),
actuated by Mechanical Coolant Pump Switch Valve N469

8. Turbocharger, bank 2 (left-side)

20. Map Controlled Engine Cooling Thermostat F265

9. Engine oil cooler

21. Non-return valve

10. Transmission Fluid Cooling Valve N509
(actuated by Transmission Control Module J217)

22. Radiator

11. Transmission Coolant Valve N488
(actuated by ECM J623)

23. Engine Coolant Temperature Sensor on Radiator
Outlet G83
24. Restrictor

12. After-Run Coolant Pump V51

25. Coolant Recirculation Pump V50

13. Starter-alternator

26. Non-return valve

Cooled coolant
Warm coolant

Thermal management
The thermal management system is responsible for
coordinating the optimal process of warming up the
engine, transmission and pas­senger compartment.
Reducing vehicle emissions is a primary concern in this
process.
During the engine warm-up phase, the engine’s mechanical
coolant pump and Coolant Recirculation Pump V50,
After-Run Coolant Pump V51 and High Temperature Circuit
Coolant Pump V467 are switched off. Transmission Fluid
Cooling Valve N509 and Transmission Coolant Valve N488
are closed. All the components listed are actuated as
needed (as calculated by the characteristic map) so that
the required coolant flow is achieved.

To provide a calculation, the characteristic map in the ECM
requires numerous input parameters:
›

Engine coolant temperature

›

Ambient air temperature

›

Engine speed, engine torque, engine power output

›

Engine oil temperature

›

Road speed

›

Heating requirements

›

Driving mode

›

Radiator outlet temperature

›

Transmission oil temperature

The following components can be activated in response:
›

Mechanical Coolant Pump Switch Valve N649

›

Map Controlled Engine Cooling Thermostat F265

›

Coolant Recirculation Pump V50, After-Run Coolant Pump V51
and High Temperature Circuit Coolant Pump V467

›

Transmission Fluid Cooling Valve N509 and Transmission
Coolant Valve N488

59

Coolant circuit in cylinder block

Connecting pipe

Distribution pipe (hot) for
ancillaries, turbocharges,
oil-coolant heat changer
Supply flow for oil-coolant heat exchanger

Return flow for
oil cooler

Connecting pipe for
coolant (cold)

Coolant return (hot)
from ancillaries directly
to coolant pump
Coolant return (hot) to
radiator via thermostat
and coolant pump

Engine water jacket with
web cooling channels and
restrictor pins

Coolant supply gallery
(cold) from radiator via
coolant pump

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60

Restrictor pins
It is very important to provide cooling to the cylinder webs
of the engine. Because they have a narrow cross-section, the
coolant does not flow through them as easily. The coolant
naturally always follows the path of least resistance.

It is not possible to do this with the casting technique used
to manufacture the cylinder block, so restrictor pins are
installed at the appropriate positions. Two restrictor pins
are installed in each cylinder bank.

To ensure that sufficient coolant can flow through the
cylinder webs, constrictions must be created at other areas
of the engine water jacket.

Restrictor pin

676_091

Engine water jacket
Restrictor pin

Cylinder web cooling

676_028

Note

When making repairs in this area, it is important to ensure that the restrictor pins are installed. Without them,
there would be no cylinder web cooling. This would cause the cylinder web areas to overheat, and certain
components would become distorted. If a cylinder head were to warp causing a head gasket leak, coolant could
leak into the combustion chamber.
61

Cooling concept for the cylinder head
The cylinder heads have the greatest cooling requirement compared to the other components in the cooling system. The
flow to cylinder block and cylinder head is distributed at a ratio of 20:80, with up to 39.62 gal (159.0 L). of coolant per
minute per cylinder head.

Breather pipe - coolant to
coolant expansion tank
in vehicle

Outlet side - coolant
outflow to distribution
gallery for crankcase
(hot)

Coolant intake passages
from coolant supply
gallery for crankcase
(cold)
676_083

Flow around valve seat
inserts (outlet side)

Flow around valve seat
inserts (inlet side)

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62

Components on the engine
View of front

Radiator return
(cold)
Mechanical Coolant Pump
Switch Valve N649
Coolant distribution