17 00 009 Checking For Coolant Leaks

WARNING: This page is about a different variant/trim than selected.

Special tools required:

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

Checking pressure drop in cooling system:

Open cap on coolant expansion tank. Fit special tools 17 0 101 / 17 0 113.17 0 100 TESTER

Build up gauge pressure, wait approx. 2 minutes.

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

Fig 1: Identifying Special Tools (17 0 101) And (17 0 113)

Courtesy of BMW OF NORTH AMERICA, INC.

Checking pressure relief valve in cap:

NOTE: While the vehicle is driven at high outside temperatures, the design may cause the pressure relief valve in the cap to open slightly and air together with dissolved coolant to escape. This coolant vapor condenses on the surface of the expansion tank and leaves traces when the vehicle has cooled down. These 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 cap to stick; therefore check the cap again 2 to 3 times.

Replace the cap only after you have checked three times and there is an incorrect opening pressure.

Checking pressure relief valve in cap:

Screw cap (1) onto special tool 17 0 11417 0 100 TESTER .

Build up pressure with special tool (hand pump) 17 0 10117 0 100 TESTER ; observe pressure gauge to ascertain when opening pressure is achieved.

Compare opening pressure of pressure relief valve.

Fig 2: Identifying Screw Cap On Special Tool (17 0 114)

Courtesy of BMW OF NORTH AMERICA, INC.