Holden commodore 2008 boiling noise

[Lorna 1987]

Pulled into my garage after using the car to hear a boiling noise coming from the yellow cap where you check the water level behind headlight made this noise before and mechanic said it was a leak near the water cap on top of engine but still did the same boiling noise. Car is not over heating and has water in both top of engine and in yellow cap. I read that the top engine bay cap should be replaced..? Help please

 

[Immortality]

Correct, the radiator pressure cap needs replacing. Boiling coolant if it's not overheating is indicating the system isn't maintaining pressure.

 

[greenacc]

Agree, and buy the new pressure cap from a Holden spares dealer if you can find one. Genuine caps are the only ones that work for me and I've tried all of them.
Makes me think I should buy a couple now for future use given that Holden dealers are disappearing faster than Trump supporters.

 

[Lorna 1987]

Thank you. I wi try find a holden one. So i should just drive the car after replacing and check. Also car has only done this couple times it wasnt each time i used after i got it checked.

 

[greenacc]

Yes that's what I would do. New cap should stop the gurgling noise and hold more pressure in the radiator. That will help the cooling system work better for the summer as well.