1 – excess pressure valve – opens at a pressure of 81.4–108 kPa; 2 – radiator cap; 3 – spring; 4 – vacuum valve spring; the vacuum valve opens at a vacuum of minus 6.86 kPa.
Checking the overpressure valve
1. Remove all foreign matter from the radiator cap valve and valve seat.
2. Attach the radiator cap to the radiator cap tester. Apply pressure to 81.4 kPa.
- Overpressure valve opening pressure: 81.4–108 kPa
- Minimum opening pressure of the overpressure valve: minus 6.86 kPa
3. After 10 seconds, check the pressure, which should not change.
4. Replace the radiator cap if necessary.
Vacuum valve valve
1. Check the spring and valve mating surfaces for damage.
2. Pull the back pressure valve to open it. Make sure that the valve closes completely when released. Attach the radiator cap to the radiator cap tester.
3. Create a vacuum until it stabilizes.
4. After 10 seconds, check the pressure, which should not change.