17 00 039 Venting cooling system and checking for leaks (M54 / M56)

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WARNING: Danger of scalding!
Only perform these tasks on an engine that has cooled down.

Necessary preliminary tasks:

E85: Remove radiator cover . See Removing Radiator Cover .

Draining coolant:

The procedure is described in the section Draining and adding coolant. See 17 00 005 Draining Off And Topping Up Coolant (M54) .

NOTE: Use only recommended coolant.

Adding coolant:

To ensure the cooling system is properly vented, it is absolutely essential to follow the steps below:

Open cap (1) on coolant expansion tank.
Open vent screw (2).
Switch on ignition.
Set heater control to maximum temperature.
Set fan to lower speed (so that heater valves open).
Fill with coolant slowly.
Close vent screw (2) when bubble-free coolant emerges.

Fig 1: Opening Coolant Expansion Tank Cap
Courtesy of BMW OF NORTH AMERICA, INC.
Pour coolant into coolant expansion tank up to max. cold fill level. Marking (2) is then on a level with upper edge of coolant expansion tank.
Close coolant expansion tank
Allow engine to warm up until thermostat opens

Fig 2: Locating Expansion Tank Coolant Filling Mark (E 65/E 66) (1 Of 2)
Courtesy of BMW OF NORTH AMERICA, INC.

Checking coolant level:

CAUTION: Check coolant level at a maximum coolant temperature of 30°C.

NOTE: If ambient temperature exceeds 30°C, allow engine to cool down at least to ambient temperature.

Open cap carefully.

Fluid level is O.K. when top edge of coolant expansion tank is between both markings (1 and 2) on float needle.

Minimum cold fill level:

Upper edge of coolant expansion tank is level with marking (1).

Maximum cold fill level:

Upper edge of coolant expansion tank is level with marking (2).

If necessary, top up coolant.

NOTE: Tank mark indicates the fluid level at approx. 20°C.

Check cooling system for leaks. See 17 00 009 Checking Cooling System For Leaks (M54) .

Fig 3: Locating Expansion Tank Coolant Filling Mark (E 65/E 66) (2 Of 2)

Courtesy of BMW OF NORTH AMERICA, INC.