It is necessary to replace the coolant after carrying out any work on the elements of the cooling system with draining the coolant. If during the repair the cylinder head, head gaskets, radiator or oil heat exchanger were replaced, fresh coolant must be poured into the cooling system. This is due to the fact that the anti-corrosion additive in the coolant is deposited during engine operation and creates anti-corrosion protection. In used coolant, anti-corrosion additives are less active in order to form a protective layer on newly installed parts.
Drained coolant must be collected and disposed of.
Warning: When opening the expansion tank cap on a hot engine, care must be taken as escaping vapors can cause severe burns. To do this, close the expansion tank cap with a thick layer of cloth and slowly unscrew it until a hissing sound is heard. After the hiss stops, slowly unscrew and remove the cap from the expansion tank.
Raise the front of the car and place it on stands. Remove the expansion tank cap.
Pic. 3.1–1. The location of the fastening latches of the lower mudguard of the engine compartment
Release the clips and remove the lower mudguard of the engine compartment (see fig. 3.1–1).
Install a VAG 1306 receiving pan under the engine to collect the coolant.
Pic. 7–5. Radiator drain plug location
Unscrew the screw plug from the radiator (pic. 7–5) and drain the coolant. To prevent coolant from spilling, insert a hose instead of the screw plug.
Pic. 3.1–3. Duct location (1) and collars (2 and 3) coolant hose fittings
Loosen clamp, remove hose 3 (see fig. 3.1–3) and drain the coolant into the sump.
Loosen the clamp, remove the hose, move it down and drain the coolant from the radiator.
Pic. 3.1–4. Location of the oil filter and oil heat exchanger: 1 - hose; 2 - oil filter; 3 - oil heat exchanger
Disconnect the additional coolant hose at the bottom of the oil heat exchanger and drain the coolant into a sump (see fig. 3.1–4).
Pic. 3.1–5. Location of the coolant drain plug from the engine block
Remove the coolant drain plug from the engine block (see fig. 3.1–5).
When installing the plug, a new sealing ring must be used.
For a more complete drain of the coolant, apply air under pressure through the plug of the expansion tank.
If the coolant is heavily contaminated, flush the cooling system. Since the coolant cannot be completely drained from the cooling system, it is recommended to flush the cooling system each time the coolant is drained.
Screw the coolant drain plug with a new O-ring into the water pump housing and tighten to 20 Nm.
Install the lower engine mudguard and lower the vehicle to the ground.
Move the temperature control of the heating system to the maximum temperature position.
Pic. 7–6. The location of the plugs for removing air from the cooling system of a 2.8 l gasoline engine
Unscrew the two air bleed plugs located on the pipes of the cooling system near the expansion tank (pic. 7–6).
Instead of the expansion tank cap, screw in the VAG 1274/1 threaded adapter with a tube 42 mm in diameter and 100 mm high. This is necessary in order to completely fill the engine cooling system with coolant and remove air from it. In the absence of a special device, you can make it yourself. Alternatively, the expansion tank can be unscrewed from the bracket, lifted up to a height of 10 cm, together with the connected hoses, and secured in this position.
Pour coolant into the expansion tank until it flows out through the vent plugs. Screw on the plugs with a torque of 20 Nm.
Remove the tool that was installed instead of the cap from the expansion tank and screw the cap onto the expansion tank.
Pic. 7–7. Location of the electrical connector of the valves of the gasoline engine 2.8 l
Disconnect the electrical connector (pic. 7–7) from valves.
Set the heater temperature switch to the minimum temperature position.
Start the engine and let it run for 3 minutes at 2000 rpm.
Check the coolant level and top up if necessary.
On a hot engine, the coolant level should be at the level of the max mark, on a cold engine between the marks max and min.
Coolant Composition
It is not recommended to use the previously used mixture of antifreeze and anti-corrosion agent G11, which is green. Do not mix G11 and G12 Anti-Corrosion Agents as this may cause severe engine damage.
If the cooling system was filled with coolant that is not recommended by the manufacturer, drain it from the cooling system. Pour clean water into the cooling system, start the engine and let it idle for 2 minutes. Drain the water from the cooling system and blow out the engine cooling system with compressed air through the expansion tank. Fill with fresh coolant recommended by the manufacturer.
Visitor comments