Whistling Astra ECO..............

Turbo?

Ah ok
If I remember on the early H astra s a whistling noise was a common issue to do with the engine breather system leaking at certain rpm.

Cheers gents and yeah Gaz they're the exact symptoms. Diaphragm removed from inside the rocker, still whistles and lots of vacuum too with the added bonus of a top coolant hose collapsing until pressure released.

I know a modified rocker cover is available but it aint cheap (150+), coolant hose suggests head gasket but the massive vacuum suggests breathers.

Anyone had both go? or is that a common symptom of the dreaded breather issue too?

I've been shown one where I think it was the intake hose was collapsing and asked if I had ever seen that before. Could of been a coolant hose, I didn't pay much attention as the engine was running that rough. I removed the oil cap and it settled down so told him he needed the cover replaced. Once done was all fine.

Where is the whistling noise coming from?