Checking cooling system for watertightness (Cooper)

Special tools required:

17 0 101
17 0 102
17 0 109
17 0 115
17 0 100

WARNING: Risk of burning and scalding!

Only perform this repair work after engine has cooled down.

IMPORTANT: Open cooling system only when it has cooled down.

Opening the cooling system while hot can result in air entering the system.

This can cause overheating with permanent damage to the engine!

Preliminary work needed:

Follow NOTES for carrying out repair work on the cooling system.

Checking pressure drop in cooling system:

Unscrew sealing cap from coolant filler neck.

Connect special tool 17 0 109 to the coolant filler neck.

Connect special tools 17 0 102 and 17 0 101.

BUILD UP EXCESS PRESSURE (technical data) and wait approx. 2 minutes.

Cooling system is tight if pressure drop does not exceed 0.1 bar.

Courtesy of BMW OF NORTH AMERICA, INC.

Checking pressure relief valve in sealing cap:

NOTE: While driving at high outside temperatures, the design may cause the pressure relief valve in the sealing cap to open slightly and air together with released coolant to leak. This coolant vapor condenses on the surface of the expansion tank and leaves traces of coolant after the vehicle has cooled down. These coolant traces do not indicate whether the cap is defective or not. Additionally, after an extended vehicle standstill, the residual leakage coolant can cause the pressure relief valve in the sealing cap to stick; therefore repeat the test procedure on the sealing cap 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 on sealing cap (1) on special tool 17 0 115 from the set of special tools 17 0 100.

Use special tool (hand pump) 17 0 101 from the special tool set 17 0 100 to build up pressure; observe pressure gauge to ascertain when opening pressure is achieved.

Compare opening pressure of PRESSURE RELIEF VALVE (technical data).

Courtesy of BMW OF NORTH AMERICA, INC.