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Home >> BMW >> 2012 >> 335is 2D Convertible, Automatic DCT Trans >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Cooling System - Repair - E93 >> Coolant, Checking Cooling System >> 17 00 009 Checking cooling system for water leaks

17 00 009 Checking cooling system for water leaks

Special tools required: 

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

Protective measures/rules of conduct 

IMPORTANT: Risk of slipping due to coolant on the floor.
Risk 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: Identifying Coolant Drip Tray And Special Tool (00 2 030)
G09858869Courtesy of BMW OF NORTH AMERICA, INC.

Checking pressure drop in cooling system 

Open cap on coolant expansion tank. Fit special tool 17 0 101 /17 0 113 .

BUILD UP GAUGE PRESSURE , wait approx. 2 minutes.

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

Fig 2: Checking Pressure Drop In Cooling System
G09858870Courtesy 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 sealing 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 0 114 .

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: Checking Pressure Relief Valve In Cap
G09858871Courtesy of BMW OF NORTH AMERICA, INC.