Vauxhall Workshop Service and Repair Manuals

Engine, Check for Leaks, (CO Content in Cooling System)  

Engine at operating temperature (oil temperature ≥ 80 ° C/176 ° F).  

  Inspect   

With engine running, place tester on coolant compensation tank.   By operating the rubber bellows the air will be sucked out of the coolant compensation tank - no coolant must be sucked up in the process. If the blue fluid in the upper chamber of the test device turns yellow the cylinder head seal or the cylinder head is leaking.

Procedure: The transparent cylinder of the tester contains a blue reaction fluid which turns yellow when exposed to air which contains the slightest amounts of carbon monoxide. When the test fluid is exposed to fresh air, it regenerates, i.e. turns blue again.  

The fluid can be tested by exposing it to fumes from the exhaust pipe, which should cause it to turn yellow.