Peugeot 405 Manual

Coolant renewal (24000 Mile (40 000 km) / 2 Year Service)
Routine maintenance and servicing / Coolant renewal (24000 Mile (40 000 km) / 2 Year Service)


Note: On models from 1994, the makers specified interval for this procedure is every 2 years, regardless of mileage.

Cooling system draining
Warning: Wait until the engine is cold before starting this procedure. Do not allow
antifreeze to come in contact with your skin, or with the painted surfaces of the vehicle. Rinse off spills immediately with plenty of water. Never leave antifreeze lying around in an open container, or in a puddle in the driveway or on the garage floor. Children and pets are attracted by its sweet smell, but antifreeze can be fatal if ingested.

1 With the engine completely cold, remove the expansion tank filler cap. Turn the cap anti-clockwise until it reaches the first stop.

Wait until any pressure remaining in the system is released, then push the cap down, turn it anti-clockwise to the second stop, and lift it off.

2 Position a suitable container beneath the coolant drain outlet at the lower left-hand side of the radiator.

3 Loosen the drain plug (there is no need to remove it completely) and allow the coolant to drain into the container. If desired, a length of tubing can be fitted to the drain outlet to direct the flow of coolant during draining (see illustration).

20.3 Radiator drain outlet (arrowed)
20.3 Radiator drain outlet (arrowed)

4 To assist draining, open the cooling system bleed screws. On all except 1.4 litre engines, the bleed screws are located in the thermostat cover and thermostat housing. On 1.4 litre engines, the bleed screws are located in the thermostat housing, and in the cylinder head coolant bypass hose. Additionally, on 2.0 litre XU10J4 engines, there is a bleed screw located in the coolant bypass hose behind the cylinder head. All models also have a bleed screw located at the top left-hand corner of the radiator (see illustrations).

20.4a Cooling system bleed screws on thermostat housing and cover (arrowed) -
20.4a Cooling system bleed screws on thermostat housing and cover (arrowed) - 1.6 litre engine shown

20.4b Coolant bypass hose bleed screw (arrowed) - 1.4 litre engine
20.4b Coolant bypass hose bleed screw (arrowed) - 1.4 litre engine

20.4c Radiator bleed screw (arrowed)
20.4c Radiator bleed screw (arrowed)

5 On 1.4 litre and 2.0 litre engines, when the flow of coolant stops, reposition the container below the cylinder block drain plug. On 1.4 litre engines, the drain plug is located at the front left-hand end of the cylinder block. On 2.0 litre engines, the drain plug is located at the rear left-hand end of the cylinder block, next to the rear engine mounting (see illustrations).

20.5a Cylinder block drain plug location (arrowed) - 1.4 litre engine
20.5a Cylinder block drain plug location (arrowed) - 1.4 litre engine

20.5b Cylinder block drain plug location (arrowed) - 2.0 litre engine
20.5b Cylinder block drain plug location (arrowed) - 2.0 litre engine

On 1.6, 1.8 and
1.9 litre engines, no cylinder block drain plug is fitted.

6 Where applicable, remove the cylinder block drain plug, and allow the coolant to drain into the container.

7 If the coolant has been drained for a reason other than renewal, then provided it is clean and less than two years old, it can be re-used, though this is not recommended.

8 Refit and tighten the radiator and cylinder block drain plugs, as applicable, on completion of draining.

Cooling system flushing
9 If coolant renewal has been neglected, or if the antifreeze mixture has become diluted, then in time, the cooling system may gradually lose efficiency, as the coolant passages become restricted due to rust, scale deposits, and other sediment. The cooling system efficiency can be restored by flushing the system clean.

10 The radiator should be flushed independently of the engine, to avoid unnecessary contamination.

Radiator flushing
11 To flush the radiator, first tighten the radiator drain plug, and the radiator bleed screw, where applicable.

12 Disconnect the top and bottom hoses and any other relevant hoses from the radiator, with reference to Chapter 3.

13 Insert a garden hose into the radiator top inlet. Direct a flow of clean water through the radiator, and continue flushing until clean water emerges from the radiator bottom outlet.

14 If after a reasonable period, the water still does not run clear, the radiator can be flushed with a good proprietary cleaning agent. It is important that the manufacturers instructions are followed carefully. If the contamination is particularly bad, insert the hose in the radiator bottom outlet, and reverse-flush the radiator.

Engine flushing
15 To flush the engine, first refit and tighten the cylinder block drain plug (where applicable), and tighten the cooling system bleed screws.

16 Remove the thermostat as described in Chapter 3, then temporarily refit the thermostat cover.

17 With the top and bottom hoses disconnected from the radiator (see Chapter 3 - it may be preferable to disconnect the bottom hose from the engine), insert a garden hose into the radiator top hose. Direct a clean flow of water through the engine, and continue flushing until clean water emerges from the radiator bottom hose.

18 On completion of flushing, refit the thermostat and reconnect the hoses with reference to Chapter 3.

Cooling system filling
19 Before attempting to fill the cooling system, make sure that all hoses and clips are in good condition, and that the clips are tight.

Note that an antifreeze mixture must be used all year round, to prevent corrosion of the engine components (see following sub- Section). Also check that the radiator and cylinder block drain plugs, as applicable, are in place and tight.

20 Remove the expansion tank cap.

21 Open all the cooling system bleed screws (see paragraph 4).

22 Some of the cooling system hoses are positioned at a higher level than the top of the radiator expansion tank. It is therefore necessary to use a header tank when refilling the cooling system, to reduce the possibility of air being trapped in the system.

Although Peugeot dealers use a special header tank, the same effect can be achieved by using a suitable bottle, with a seal between the bottle and the expansion tank (see illustration and Haynes Hint).

20.22 Peugeot cooling system header tank in position
20.22 Peugeot cooling system header tank in position

23 Fit the header tank to the expansion tank and slowly fill the system. Coolant will emerge from each of the bleed screws in turn, starting with the lowest screw. As soon as coolant free from air bubbles emerges from the lowest screw, tighten that screw, and watch the next bleed screw in the system.

Repeat the procedure until the coolant is emerging from the highest bleed screw in the cooling system and all bleed screws are securely tightened. Keep the header tank full during this procedure.

24 Once all the bleed screws are securely tightened, remove the header tank and refit the expansion tank cap.

25 Start the engine, and run it at 1500 rpm.

Maintain this engine speed until the radiator cooling fan has cut in and out three times.

26 Allow the engine to run at idle speed for a few minutes.

27 Stop the engine, and wait for at least ten minutes.

28 Place a large wad of rag around the expansion tank cap, and around your hand, then carefully remove the expansion tank cap.

Turn the cap anti-clockwise until it reaches the first stop. Wait until any pressure remaining in the system is released, then push the cap down, turn it anti-clockwise to the second stop, and lift it off.

Warning: Take precautions against scalding, as the cooling system will be hot.

29 Check the coolant level, and if necessary top-up the expansion tank to just above the MAXI level mark (see Weekly checks).

30 Refit the expansion tank cap.

Antifreeze mixture
31 The antifreeze should always be renewed at the specified intervals. This is necessary not only to maintain the antifreeze properties, but also to prevent corrosion which would otherwise occur as the corrosion inhibitors become progressively less effective.

32 Always use an ethylene-glycol based antifreeze which is suitable for use in mixedmetal cooling systems. The quantity of antifreeze and levels of protection are indicated in the Specifications.

33 Before adding antifreeze, the cooling system should be completely drained, preferably flushed, and all hoses checked for condition and security.

34 After filling with antifreeze, a label should be attached to the expansion tank, stating the type and concentration of antifreeze used, and the date installed. Any subsequent topping-up should be made with the same type and concentration of antifreeze.

35 Do not use engine antifreeze in the windscreen/tailgate washer system, as it will cause damage to the vehicle paintwork. A screenwash additive should be added to the washer system in the quantities stated on the bottle.


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