Checking For Coolant Leaks

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

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

Checking Pressure Drop In Cooling System:

Remove cap on expansion tank. Attach special tool 17 0 002/17 0 005.

Build up gauge pressure of 1.5 bar, wait approx. 2 minutes.

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

Fig 1: Pressure Testing Cooling System

Courtesy of BMW OF NORTH AMERICA, INC.

Checking Pressure Relief Valve In Cap:

Detach rubber (1) from hand pump.

Attach special tool 17 0 007/17 0 008.

Fig 2: Detaching Rubber From Hand Pump

Courtesy of BMW OF NORTH AMERICA, INC.

Screw cap (1) onto special tool.

Build up pressure with special tool (hand pump) 17 0 002; observe pressure gauge to ascertain when opening pressure is achieved.

Compare opening pressure of pressure relief valve.

Fig 3: Checking Radiator Cap Pressure Relief Valve

Courtesy of BMW OF NORTH AMERICA, INC.

Checking Vacuum Valve In Cap

Screw cap (1) onto special tool 17 0 007 and connect to vacuum hose of vacuum pump.

Fig 4: Checking Radiator Cap Vacuum Valve

Courtesy of BMW OF NORTH AMERICA, INC.

Feed vacuum pump with battery positive voltage.

Slowly apply partial vacuum to cap.

Compare opening pressure of vacuum valve.