17 00 009 Checking watertightness of cooling system (N63 B40/B44 O 1, N74)

Special tools required:

WARNING: Risk of scalding!
Only perform this repair work after engine has cooled down.

Protective measures/rules of conduct:

Wear safety goggles
Wear protective gloves
Observe national/country-specific regulations

IMPORTANT: Risk of skidding due to coolant on the floor.
Danger of injury!

Catch and dispose of drained coolant in drip tray (1) and if necessary special tool 00 2 030 (universal hydraulic lifting equipment).

Recycling:

Observe country-specific waste disposal regulations.

Fig 1: Supporting Coolant Drip Tray Using Special Tool (00 2 030)

Courtesy of BMW OF NORTH AMERICA, INC.

Checking pressure drop in cooling system:

Open the sealing cap on the coolant expansion tank. Fit special tools (1) 17 0 101 and (2) 17 0 113 .

Build up GAUGE PRESSURE and wait approx. 2 minutes.

Cooling system is impervious to watertightness if pressure drop is max. 0.1 bar.

Fig 2: Checking Pressure Drop In Cooling System

Courtesy of BMW OF NORTH AMERICA, INC.

Checking pressure relief valve in sealing cap:

NOTE: While driving the vehicle at high outside temperatures, depending on the design, the pressure relief valve in the sealing cap can open slightly and air, together with dissolved coolant, can escape. This coolant vapor condenses on the surface of the expansion tank and leaves traces of coolant when the vehicle has cooled down. These coolant traces do not indicate whether the cap is defective or not. When the vehicle has been parked up for an extended period of time, the residual escaping coolant can cause the pressure relief valve in the sealing cap to stick; therefore check the sealing cap again 2 to 3 times.
Replace the sealing cap only after you have checked three times and there is an incorrect opening pressure.

Checking pressure relief valve in sealing cap:

Screw sealing cap (1) onto special tool 17 0 114 .

Build up pressure with special tool (hand pump) 17 0 101 ; observe pressure gauge to ascertain when opening pressure is achieved.

Compare OPENING PRESSURE of pressure relief valve.

Fig 3: Identifying Cooling System Pressure Tester

Courtesy of BMW OF NORTH AMERICA, INC.