Checking Cooling System For Leaks

CAUTION: The cylinder head gasket is not watertight until the engine has reached operating temperature, in other words until a swelling operation has taken place. For this reason, the cooling system MUST NOT be pressure tested until after the engine has reached operating temperature.

1. Open 2 stage cap half a turn to release pressure and then unscrew.
2. Take off cap.





NOTE:
^ A 2-stage cap is installed in the expansion reservoir. The 2-stage cap eliminates the need for the overflow reservoir. The pressure in the cooling system may rise during the "Engine Off" heating phase (after switching off engine). The first stage in the coolant cap opens at 1.4 bar; the cooling system remains closed, however. 2nd stage in the coolant cap opens at 2.0 bar that coolant flows out to atmosphere along several vent drillings (a), the ring duct (b) into the outlet connection (c) and along a hose extension.
^ The cap must not be opened unless the coolant temperature is below 90° C.

3. Check coolant level and adjust to correct level.
- Pour in coolant up to the marking (cast lug) on the bottom of the expansion reservoir.





4. Pressurize cooling system to about 1.4 bar with the test cap and the tester.
5. Examine all the cooling and heating water hoses and their connection points for loss of coolant.
6. Check condition of coolant hoses and hose clips; replace or re-tighten if necessary.