Strange engine noise 2009 C30 T5 (with video) Topic is solved

[GregUSA]

I have a 2009 C30 T5 that recently has developed a very strange noise from the engine compartment. I couldn't describe it so I shot a short video for you. About the same time the noise started, give or take a day or so, the 'check engine' light came on and has stayed on (still on).

What really has me stumped is that this sound is loudest/most obvious at idle, or whenever my foot is off the gas pedal (or when I let up off the accelerator). The moment I press down on the gas pedal - the sound almost completely goes away. When I let off the gas pedal - the sound is back instantly.

The car was just in for regular service/oil change about a month ago. No obvious problems in the engine compartment were noted at that time.

Open to any suggestions as to what might be causing this. It really just popped up out of the blue one day. Thanks - Greg

https://www.youtube.com/watch?v=1OIRsXa ... e=youtu.be

[kmason1296]

Once it starts making the noise, try pulling the oil dipstick. If the noise stops it is a oil trap leak. Some bladder in there makes the noise when the pressure increases. My volvo dealer says driving it that way won't hurt anything in the short term. It is just annoying as all get out. My 2011 T5 C30 has 95,000K. I have maintained meticulously, but I just developed the problem. It is presently being replaced. PCV Breather System Kit for the the C30. I am also preemptively replacing the timing belt as I fully intend to drive my black beauty another 100K. I absolutely love my C30.

[Ladder20Roof]

Where you getting any cel codes when that was happening? I have the same noise but I'm getting a throttle body code

[GregUSA]

The repair shop mentioned there were codes but sorry, I don't recall what they told us about that.