Checking low-temperature cooling system for watertightness
WARNING:
Hot surfaces.
Risk of burning!
Risk of burning!
- Perform all work only on components that have cooled down.
- Loosen sealing cap (1) .
- Attach the special tool 0 494 418 (17 0 101) with the special tools 0 494 419 (17 0 102) and 0 494 426 (17 0 109) from the set of special tools 0 494 417 (17 0 100) .
- Build up excess pressure and wait for approximately 2 minutes.
TECHNICAL DATA SPECIFICATION
| Opening pressure of sealing cap of low-temperature coolant circuit | ||
| Pressure relief valve opens when the pressure exceeds the ambient pressure. | min. 1.4 bar | |
| Electric changeover valve must open at latest when the pressure is lower than the ambient pressure | max. 0.1 bar | |
| Test pressure for cooling system (gauge pressure) | 1.5 bar | |
NOTE:
TECHNICAL INFORMATION
If the test step described 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 outside temperatures, the pressure relief valve in the sealing cap may open slightly due to its design, causing air to escape in combination 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.
The escaping coolant vapors can also cause the pressure relief valve in the sealing cap to stick when the vehicle is stationary for a longer period. This may cause an incorrect opening pressure.
If the test step described 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 outside temperatures, the pressure relief valve in the sealing cap may open slightly due to its design, causing air to escape in combination 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.
The escaping coolant vapors can also cause the pressure relief valve in the sealing cap to stick when the vehicle is stationary for a longer period. This may cause an incorrect opening pressure.
- Screw on sealing cap (1) on special tool 0 495 889 (17 0 115) from the set of special tools 0 494 417 (17 0 100) .
- Build up the pressure with special tools 0 494 418 (17 0 101) and 0 494 419 (17 0 102) from the set of special tools 0 494 417 (17 0 100) .
- Observe on the pressure tester when the opening pressure has been reached.
TECHNICAL DATA SPECIFICATION
| Opening pressure of sealing cap of low-temperature coolant circuit | ||
| Pressure relief valve opens when the pressure exceeds the ambient pressure. | min. 1.4 bar | |
| Electric changeover valve must open at latest when the pressure is lower than the ambient pressure | max. 0.1 bar | |
| Test pressure for cooling system (gauge pressure) | 1.5 bar | |
- Close sealing cap (1) .