oil temperature AUDI A4 2000 B5 / 1.G AFC Engine Lubrication System Components Workshop Manual

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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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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17-12

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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