Hi
I drive a Gen 2 diesel, and picked up a strange noise coming from the engine bay yesterday. It sounds like a valve opening and air being release under pressure.
* It only occurs when I'm accelerating hard - no noise when driving at light throttle or at idle
* Only occurs when driving or car is in gear. Revved the engine while in neutral, no noise.
* Checked all the pipes. All are on tight, no visible signs of damage on pipes or intercooler.
* No power loss, engine temp is normal, no warning lights.
Any ideas what it might be or where to start looking?
My Gen2 did the same. Turned out to be the safety pressure valve on the back of the intake manifold, close to the firewall and next to the clutch master cylinder. I fitted a boost gauge to the system and after checking that the pressures were staying below 1.1 bar and the waste gate was opening, I blanked it off. That is not recommended though as you are removing a backup should the wastegate fail.
It has an internal spring that weakens after time and then "blows" off the boost like a STI
It has an internal spring that weakens after time and then "blows" off the boost like a STI