oil pressure AUDI A4 1999 B5 / 1.G AFC Engine Lubrication System Components Workshop Manual

17-1


Lubrication system
components, removing and
installing Special tools

The following special tools and test equipment are
required for these operations
VAG 1342
Oil pressure tester
VAG 1527
Voltage tester
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6 -
Oil pan, lower
7 -
10 Nm (7 Nm)
8 -
Oil drain plug
40 Nm (30 ft lb)
9 -
Cover With integrated 5 bar (72 psi) and 11 bar
(159 psi) pressure relief valves
10 -
Oil cooler
11 -
Oil filter NOT interchangeable with older versionRevised lubrication system requires
different filter: Part no. 078 115 561 D
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17-6


Revised oil circulation system

Note:

Modifications compared to previous 2.8 liter V6
(Audi 90, Audi 100).
Only the modified components should be
installed on this engine.
1 -
Oil filter
Larger outer dimensions
2 -
Oil cooler Larger cross-sectional flow area
3 -
Cover for oil pan New
4 -
Pressure relief valve New
5 -
Oil supply to engine
6 -
Oil pump New
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7 -
Pressure relief valve 11 bar
New
8 -
Oil pick-up New
9 -
Oil pressure switch 1.8 bar Color: BrownChecking page 17
-9
Dynamic oil pressure warning system
function page 17
-11

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17-8


Function of revised oil circulation
Intake side
Oil is taken in from the oil pump -6- via the oil pick-
up pipe -8-.
Pressure side
Oil pressure comes from the oil pump -6- through
the upper part of the oil pan past the pressure relief
valve -7-, oil pressure switch -9-, oil cooler -2- and
oil filter -1- to the pressure relief valve -4-.
Pressure relief valve -4- controls the oil pressure to
the engine.
The pressure relief valve -7- is a safety valve that
opens only at high RPM and cold engine
temperature.
Advantages
Oil pressure is controlled from the oil filter and oil
cooler, so that the oil pressure available at those
locations is supplied via the pressure relief valve -4-
or from the oil pump.
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17-9

Oil pressure and oil pressure switch,
checking

Operational test and servicing the visible and
audible oil pressure indicator:

Electrical Wiring Diagrams, Troubleshooting
Component Locations binder.

Test requirements

Oil level OK
Oil pressure warning light -K3- comes on
with ignition on
Auto-Check system indication OK, if
applicable.
Engine oil temperature approx. 80 C (176
F) and radiator coolant fan must have
switched on at least once

Checking oil pressure switch

- Disconnect harness connector from oil pressure
switch.
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- Remove oil pressure switch and install into oil pressure tester VAG
1342.
- Connect cable -2- (brown) to Ground (GND).
- Connect cable -1- (blue) to oil pressure switch.
- Connect VAG 1527B voltage tester to cable -1- and battery positive
voltage (B+).
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- Start engine and slowly increase engine speed
(RPM).

At 1.6-2.0 bar (23-29 psi) pressure, the LED
must come on
If not:

- Replace 1.8 bar oil switch.
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17-11

Operation of dynamic oil pressure
warning system, checking

Testing oil pressure warning light:
After ignition is switched on (terminal 15 on) with
the engine not running, the oil pressure warning
light flashes (not on models with Auto Check
System).
Warning criteria:

Engine not running; oil pressure switch
closed
Engine coolant temperature greater than 60 C
(140 F), engine speed greater than 1500 RPM
and oil pressure switch open

Engine coolant temperature less than 60 C
(140 F), engine speed greater than 300 RPM
and oil pressure switch open

At an engine speed greater than 5000 rpm, an
active oil warning is not cancelled, irrespective
of the position of the oil pressure switch
If the voltage supply to the control module
(terminal 15) is in order and, when the engine is
running, the oil pressure switch is open for
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Testing oil pressure

Oil pressure specifications - Remove oil pressure switch and screw in VAG 1342 oil pressure
gauge.
(The oil pressure sensor shown in the illustration is not installed on the
A4)
- Install oil pressure switch into VAG 1342.
- Start engine.
Engine oil temperature at least 80 C (176 F) At idle: 1.0-2.5 bar (15-36 psi)At 3000 RPM: 3.0-5.0 bar (44-73 psi)
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