Special tools required:

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: Checking Cooling System For Water Leaks

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Checking pressure relief valve in cap:

Detach rubber (1) from hand pump.

Attach special tool 17 0 007 / 17 0 008.

Fig 2: Removing Rubber From Hand Pump

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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: Installing Screw Cap Onto Special Tool

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.

Feed vacuum pump with battery positive voltage.

Slowly apply partial vacuum to cap.

Compare opening pressure of vacuum valve.

Fig 4: Identifying Screw Cap

Courtesy of BMW OF NORTH AMERICA, INC.