Radiator Cap: Testing and Inspection

NOTE: Numbers in parentheses ( ) indicate a component or tool in the associated illustration.

Replacement
1. Turn cap (5) anti-clockwise as far as detent 1 to release pressure.

WARNING:
^ Risk of scalding
^ Do not open cap (5) unless coolant temperature is below 90°C.

2. Attach test cap (3) tool No. 124 589 00 91 00, or equivalent, to tester (2) tool No. 124 589 24 21 00, or equivalent.
3. Attach double connection (4) tool No. 124 589 53 63 00, or equivalent, to tester (2) 124 589 24 21 00
4. Attach cap (5) to double connection (4).
5. Test opening pressure of pressure relief valve.
6. Test vacuum valve. Raise vacuum valve (6) for this step.

NOTE:
^ The vacuum valve (4) must be resting against the rubber seal (5) of the sealing plate, it must be possible to raise it easily and it must spring back when released.
^ The base for the sealing plate on the expansion tank must be flat.
^ Replace pressure cap if corroded.
^ The part No. and the pressure cap code number are stamped in the cap.

Cap code number 140:
- Pressure relief valve opens:
New: 1.4 ± 0.1 bar
Used: 1.4 - 0.1 bar
- Vacuum valve opens: 0.1 bar