Audi 80/90/Coupe

since 1986-1991 release

Repair and operation of the car



Audi 80/90/Coupe
+ 1.2. Identification of the car
+ 2. Engines, carburetors
3. Lubrication system
- 4. Cooling system
   4.2. Models with 5-cylinder engines
   4.3. Coupet's models
+ 5. Fuel system
+ 6. Exhaust system
+ 7. System of ignition
+ 8. Transmission
+ 9. Suspension brackets, wheels
+ 10. Brake system
+ 11. Steering
+ 12. Body, salon
+ 13. Air conditioning system
+ 14. Electric equipment



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4. Cooling system

4.1. Engine cooling system

GENERAL INFORMATION

Radiator in collecting (4-cylinder models)

1. Rubber plug
2. Top hose of a radiator
3. Hose of removal of air
4. Rubber-metal
plug
5. Dilator tank
test pressure
1,2–1,5 atm
6. Temperature sensor
for turning on of the fan after an engine stop for the purpose of cooling of fuel injectors
and fuel pipes
7. Dilator tank stopper
8. Spring bracket
9. Radiator casing

10. Electric fan
obduva of a radiator
11. Electric motor of the fan of an obduv of a radiator (waterproof)
12. Klinoremenny transfer of the fan
13. Radiator
at removal remove hoses and disconnect from an arm
remove a radiator with the fan and the directing device
14. Moment of an inhaling of 10 N. of m.
15. Air duct
16. Arm
17. Sealing ring
18. Fan thermoswitch
19. Lower hose of a radiator

Prevention

All laying and consolidations are subject to replacement. Without fail fix hoses by collars.

Check the cooling system by means of the equipment Snap On SVT 362 and 4467.

If in oil a significant amount of metal shaving is found, then it is necessary to clean oil channels and to replace an oil filter.

All specified details can be removed and established without dismantle of the engine from the car.


The pump cooling the liquid / thermostat in collecting (4-cylinder models)

1. Hose union
2. Top hose of a radiator
3. Pump of cooling liquid
check deformation of a shaft
at a leak or damage replace
4. Laying
5. 20 N. of m.
6. Thermostat
check immersion in hot water
temperature of operation is 8 °C
temperature of closing is 105 °C
piston stroke of a working element not less than 7 mm
7. Lower hose of a radiator
8. Oil cooler
9. Tube of cooling liquid
10. Temperature sensor
11. 10 N. of m.
12. Sealing ring
13. Sealing washer
14. Temperature sensor

Replacement of cooling liquid

The cooling system of the Audi cars of all models are filled at manufacturer with mix of water and antifreeze (G 11) with anticorrosive additives. Such cooling mix can be used all the year round.

The antifreeze which is not containing phosphates increases frost resistance, prevents corrosion and scaling, and, besides, raises a boiling point. Increase in a boiling point of cooling liquid improves operational parameters during the work with the maximum load, especially in tropical conditions.

When replacing cooling liquid in the Audi cars of all models irrespective of a year of release it is necessary to fill the cooling system with the ZVW237 102 antifreeze which is not containing phosphates.

Discharge of cooling liquid
PERFORMANCE ORDER
1) transfer the handle of management of a heater to situation warm
2) remove a stopper of a broad tank
3) merge cooling liquid or through hoses 1, or via the thermostat 2 union

Gas station

PERFORMANCE ORDER
1) establish into place and fix hoses
2) fill a broad tank with cooling liquid to maximum tag
3) close a tank a stopper
4) start the engine and warm up it before the first operation of the fan
5) check the level of cooling liquid, if necessary restore

The recommended mixes

Freezing point
Antifreeze volume
Water volume
- 25 °C
2,8 l
4,2 l
- 35 °C
3,5 l
3,5 l

Prevention

When the engine is heated-up up to the normal working temperature, the level of cooling liquid in a broad tank has to be a little higher than maximum tag. When the engine cold, the level of cooling liquid in a broad tank has to be between tags of minimum and maximum.

It is forbidden to touch fan blades. The fan can spontaneously turn on at operation of a timer. In a heated motor compartment the cycle of turning on of the fan can repeatedly be repeated after an engine stop.


Automatic turning on of the fan after an engine stop

Modern cars are equipped with system of automatic start of the fan for cooling of a fuel pipe and injectors after an engine stop that facilitates the subsequent launch of the hot engine.

Principle of work of system

If temperature in space of a motor compartment after a stop of the engine is above 110 °C, then the thermoswitch includes a timer which in turn turns on the fan.

When temperature becomes below 103 °C, the relay switches-off the fan. Such cycle can repeatedly be repeated, for 10–12 min.

System details

Thermoswitch

It is mounted on an arm which fastens to a block head between the 1st and the 2nd cylinders (from an injector).

Timer

After operation of a thermoswitch, a timer turns on the fan on the first speed of rotation for 10–12 min. after an engine stop.

Fan thermoswitch – operation thresholds
Switch
Temperature of inclusion / switching off
incl.
off.
Three-chambered, provides connection with a positive pole of the battery, inclusion of the first speed of rotation
92 – 97 °C
84 – 91 °C
Second speed of rotation of the fan
99 – 105 °C
91 – 98 °C

Search of malfunctions

Timer

It is mounted on an auxiliary guard under the dashboard on the left side.

Turn the ignition key in position of ON and OFF.

Connect a thermoswitch wire to the mass of the car.

The fan has to turn on at the first speed of rotation.


Prevention

Test has to be executed within 10–12 minutes after an engine stop as the timer works during this period.


Thermoswitch

Position of ON – closes contact on the weight when temperature in a motor compartment is above 110 °C.

Position of OFF – contacts are opened when temperature in a motor compartment is below 103 °C.

Electrical wiring

By search of malfunctions of an electric chain you watch subsection 14.3.2.

Calibrating of the areometer for antifreeze

For ensuring accuracy of measurements, it is necessary to check calibrating of the areometer periodically.

In a small vessel mix antifreeze and water in the ratio 1:1.

The indication of the areometer has to be -35 °C. If the indication differs, then put the tag corresponding of -35 °C.

Check of level of cooling liquid

When the engine is heated-up up to the normal working temperature, the level of cooling liquid in a broad tank has to be a little higher than maximum tag.

When the engine cold, the level of cooling liquid in a broad tank has to be between tags of minimum and maximum.


The pump cooling the liquid / thermostat in collecting (5-cylinder engines)
1. 20 N. of m.
2. To the top pipe of a radiator
3. 10 N. of m.
4. To the lower pipe of a radiator
5. Adapter
6. 10 N. of m.
7. Diametrical ring laying
8. Thermostat
check immersion in hot water
temperature of operation is 87 °C
temperature of closing is 102 °C
piston stroke of a working element not less than 8,0 mm
9. Tube of cooling liquid
10. From a heater radiator
11. To a heater radiator
12. Ventilatory valve
13. 20 N. of m.
14. Diametrical ring laying
15. Thermoswitch
the providing launch of the fan after an engine stop
temperature of switching is 85 °C
16. Laying
17. Adapter
18. Sealing ring
19. Pump of cooling liquid
check deformation of a shaft
at a leak or damages replace the pump assembled

Radiator in collecting (5-cylinder engines)
1. Overlay of a radiator, top
2. 10 N. of m.
3. To an auxiliary radiator
4. Laying
5. 20 N.m
6. Rubber-metal plug, 10 N. of m.
7. Broad tank
test pressure is 1,2–1,5 atm
8. Stopper of a broad tank
9. Radiator
for dismantle remove hoses, turn out the fan thermoswitch
remove rubber-metal plugs and an overlay of a radiator
the radiator is removed assembled with the fan,
casing and the directing device

10. Rubber-metal plug, 10 N. of m.
11. Fan thermoswitch
12. Laying
13. Fan
14. To the thermostat
15. Overlay of a radiator, right
16. To a head of the block of cylinders
17. Rubber-metal plug, 10 N. of m.
18. 10 N. of m.
19. Radiator casing

Fan thermoswitch – operation thresholds
Switch
Temperature of inclusion / switching off
incl.
off.
Three-chambered, provides connection with a positive pole of the battery, inclusion of the first speed of rotation
92 – 97 °C
84 – 91 °C
Second speed of rotation of the fan
99 – 105 °C
91 – 98 °C

Calibrating of the areometer for antifreeze

For ensuring accuracy of measurements it is necessary to check calibrating of the areometer periodically.

in a small vessel mix antifreeze and water in the ratio 1:1

the indication of the areometer has to be -35 °

if the indication differs, then put the tag corresponding -35 °

Replacement of cooling liquid

The cooling system of the Audi cars of all models are filled at manufacturer with mix of water and antifreeze (G 11) with anticorrosive additives. Such cooling mix can be used all the year round.

The antifreeze which is not containing phosphates increases frost resistance, prevents corrosion and scaling, and, besides, raises a boiling point. Increase in a boiling point of cooling liquid improves operational parameters during the work with the maximum load, especially in tropical conditions.

When replacing cooling liquid in the Audi cars of all models, irrespective of a year of release, it is necessary to fill the cooling system with the ZVW237 102 antifreeze which is not containing phosphates.

The recommended mixes

Freezing point
Antifreeze volume
Water volume
- 25 °C
3,2 l
4,8 l
- 35 °C
4,0 l
4,0 l

Discharge of cooling liquid

PERFORMANCE ORDER
1) remove a stopper of a broad tank
2) disconnect a heater hose on the block of cylinders
3) disconnect transitional a hose of a tube of cooling liquid (it is specified by an arrow)

Gas station
PERFORMANCE ORDER
1) establish into place and fix hoses
2) unscrew the screw of the ventilating valve (it is specified by an arrow)
3) fill a broad tank of cooling liquid to maximum tag
4) when cooling liquid begins to be poured, wrap the screw of the ventilating valve
5) close a tank a stopper
6) start the engine and warm up it before the first operation of the fan

Cooling system components (Coupet's model)
1. Consolidation
2. Radiator guard, top section
3. 10 N. of m.
4. Rubber-metal plug, 10 N. of m.
5. Fan
6. Radiator guard, right section
7. 20 N. of m.
8. Radiator
9. Sealing washer
10. Thermoswitch, 25 N. of m.
11. Stopper of a broad tank
check: by means of VAG 1274 and VAG 1274/1A adaptation
control pressure is from 1,2 to 1,5 atm
12. Broad tank
13. Radiator casing
14. To a head of the block of cylinders
15. To the thermostat
16. To an additional radiator


Prevention

Check leaks in the cooling system by means of VAG 1274 and VAG 1274/1A adaptation.

Replace laying and consolidations. Fix all hoses by collars with fixing by the screw.


The pump cooling the liquid / thermostat in collecting (Coupet's model)

1. 20 N. of m.
2. Pump of cooling liquid
check deformation of a shaft
at a leak or damages – replace
3. Sealing ring
at a leak or damages – replace with a ring repair the size (0,5 mm, number of a detail 069 121 043)
4. Hose union
5. Laying
6. Sealing ring
7. Thermostat
check immersion in hot water
temperature of the beginning of opening of 87 °C
temperature of full opening is 102 °C
course of a working element not less than 8 mm
8. Thermoswitch
it is intended for start of the fan after an engine stop
temperature of operation is about 85 °C
9. To a radiator of an otpitel
10. To the top radiator
11. To the lower radiator
12. 10 N. of m.
13. Metal tube of cooling liquid
14. Ventilating valve
15. From a radiator of an otpitel

Replacement of cooling liquid

The cooling system of the Audi cars of all models are filled at manufacturer with mix of water and antifreeze (G 11) with anticorrosive additives. Such cooling mix can be used all the year round.

The antifreeze which is not containing phosphates increases frost resistance, prevents corrosion and scaling, and, besides, raises a boiling point. Increase in a boiling point of cooling liquid improves operational indicators of the engine during the work with the maximum load, especially in tropical conditions.

When replacing cooling liquid, or at restoration of level, it is necessary to fill the cooling system with the ZVW237 102 antifreeze which is not containing phosphates. It belongs to all models of the Audi cars, irrespective of a year of release.

The recommended mixes

Temperature of air is (not below)
Ratio of water and antifreeze
- 25 °C
3:2
- 35 °C
1:1

Discharge of cooling liquid

PERFORMANCE ORDER
1) remove a stopper of a broad tank
2) merge cooling liquid
3) remove a heater hose from a back part of the block of cylinders
4) remove the lower hose of a radiator

Gas station
PERFORMANCE ORDER
1) open the ventilating valve (it is specified by an arrow)
2) fill in cooling liquid to maximum tag on a broad tank
3) you monitor intake of liquid via the ventilating valve as soon as liquid begins to be poured, close the valve
4) close a tank a stopper
5) start the engine and warm up it before the first operation of the fan
6) check the level of cooling liquid, if necessary restore


Prevention

When the engine is heated-up up to the normal working temperature, the level of cooling liquid in a broad tank has to be a little higher than maximum tag. When the engine cold, the level of cooling liquid in a broad tank has to be between tags of minimum and maximum.


Radiator – removal

PERFORMANCE ORDER
1) remove hoses, rubber-metal plugs, the condenser of the conditioner and open a connector of conducting of a thermoswitch
2) disconnect the lower guard from a radiator and remove a radiator assembled with a casing and the fan
Prevention

On the models equipped with system of anti-blocking (ABS) it is also necessary to weaken fastening of the electric motor of the fan and to displace it forward.



Fan thermoswitch – operation thresholds

Switch
Temperature of inclusion / switching off
incl.
off.
First speed of rotation
92 – 97 °C
84 – 91 °C
Second speed of rotation of the fan
99 – 105 °C
91 – 98 °C