Astra Air Valve Vacuum Leak

I drive an Astra too, and it sounds similar to a problem I had a while back. The check engine light was on, and it turned out to be a faulty vacuum hose connected to the air valve, causing a vacuum leak. Did you check all the vacuum hoses for cracks or loose connections? That's where I'd start looking.

Could you elaborate on which specific vacuum hoses you inspected? I want to ensure I am checking the correct components. Were there any other symptoms you observed besides the check engine light that might further corroborate the diagnosis?

I checked all the hoses connected to the air pump and the valve itself. It's tricky to describe exactly which ones, but just follow them from the pump. Besides the light, the engine was stalling sometimes, especially at idle. If you're not comfortable doing it yourself, it's probably best to have a workshop take a look. They can test the system properly.

I took my car to the workshop today. You were spot on; the hose connection from pump to valve was indeed defective, resulting in a minor vacuum leak. The repair cost was 175€. Thanks; your shared insight proved invaluable.