Checking cooling system for watertightness
WARNING:
Hot surfaces.
Risk of burning!
Risk of burning!
- Perform all work only on components that have cooled down.
- Release sealing cap on the coolant expansion tank.
Check
- Mount special tool 17 0 101 with 17 0 102 and 17 0 113 from the set of special tools 0 494 417 (17 0 100) onto coolant expansion tank.
- Use the special tool 17 0 101 to build pressure of 1.5 bar in the cooling system.
Desired state
- Pressure of 1.5 bar must be maintained for 2 minutes.
Result
» Pressure in the cooling system drops.
Measure
- Find and fix leak in cooling system.
Check
NOTE:
TECHNICAL INFORMATION
If the described test step is not completed successfully: repeat test step twice. Only replace the sealing cap after three tests with an incorrect opening pressure.
When driving at high ambient temperatures, the design may cause the pressure relief valve in the sealing cap to open slightly and air to leakage together with dissolved coolant. This coolant vapor condenses on the surface of the coolant expansion tank and leaves traces of coolant when the vehicle has cooled down. These traces of coolant do not indicate whether the sealing cap is defective or not.
Leakage coolant vapors when the vehicle is at standstill may cause the pressure relief valve to stick to the sealing cap. This may cause an incorrect opening pressure.
If the described test step is not completed successfully: repeat test step twice. Only replace the sealing cap after three tests with an incorrect opening pressure.
When driving at high ambient temperatures, the design may cause the pressure relief valve in the sealing cap to open slightly and air to leakage together with dissolved coolant. This coolant vapor condenses on the surface of the coolant expansion tank and leaves traces of coolant when the vehicle has cooled down. These traces of coolant do not indicate whether the sealing cap is defective or not.
Leakage coolant vapors when the vehicle is at standstill may cause the pressure relief valve to stick to the sealing cap. This may cause an incorrect opening pressure.
- Screw on sealing cap on special tool 17 0 114 from the set of special tools 0 494 417 (17 0 100) .
- Use special tools (hand pump) 17 0101 and 17 0102 from the set of special tools 0 494 417 (17 0 100) to build up pressure; observe pressure tester to ascertain when opening pressure is achieved.
Desired state
- Opening pressure of the sealing cap is 2 bar.
Result
» Sealing cap opens before or after 2 bar.
Measure
- Replace sealing cap.