Check the high-temperature cooling system for watertightness
WARNING: This page is about a different car, the 2025 BMW M4, 2024 BMW M4, 2023 BMW M4, 2022 BMW M4, and 2021 BMW M4. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:
Hot surfaces
.
Risk of burning!
Risk of burning!
- Perform all work only on components that have cooled down.
- Loosen sealing cap (1).
- Set up the special tool 0 494 418 (17 0 101) on the coolant expansion tank with special tool 0 494 419 (17 0 102) and special tool 0 494 642 (17 0 113) 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
| Cooling system test pressure | |
| Test pressure for cooling system (gauge pressure) | 2.0 bar |
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 (1) on special tool 0 494 643 (17 0 114) from the set of special tools 0 494 417 (17 0 100) .
- Build up the pressure with the special tool 0 494 418 (17 0 101) and the special tool 0 494 419 (17 0 102) from the special tool set 0 494 417 (17 0 100) .
- Observe on the pressure tester when the opening pressure has been reached.
TECHNICAL DATA SPECIFICATION
| Opening pressure of coolant seal cover | |
| 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 |
- Close sealing cap (1).
- Close the sealing cap (1) until the arrows align.