[jeffknutson56]

I have noticed in my new (to me) 2018 6MT that when I am accelerating and lift off the throttle, I hear a 'groan' noise from the engine bay that lasts for a fraction of a second. It doesn't happen while cruising, turning, idling, or anything. Only when I accelerate and lift off the pedal. It almost sounds like a wood chair on a wood floor, or like a balloon rubbing against another balloon. Very low pitched. This has been happening for about a week, and I haven't noticed any other issues (no loss of power, no high temp, no MPG drops).

Any idea what might be causing this?

 

[2018sport6MT]

I have noticed in my new (to me) 2018 6MT that when I am accelerating and lift off the throttle, I hear a 'groan' noise from the engine bay that lasts for a fraction of a second. It doesn't happen while cruising, turning, idling, or anything. Only when I accelerate and lift off the pedal. It almost sounds like a wood chair on a wood floor, or like a balloon rubbing against another balloon. Very low pitched. This has been happening for about a week, and I haven't noticed any other issues (no loss of power, no high temp, no MPG drops).

Any idea what might be causing this?

could it be something with the turbo? "for a fraction of a second" sounds like that groaning is the same type of sound a blowoff valve would make; a quick, short sound only made when lifting off the throttle when accelerating.

 

[PublicPotato]

I have noticed in my new (to me) 2018 6MT that when I am accelerating and lift off the throttle, I hear a 'groan' noise from the engine bay that lasts for a fraction of a second. It doesn't happen while cruising, turning, idling, or anything. Only when I accelerate and lift off the pedal. It almost sounds like a wood chair on a wood floor, or like a balloon rubbing against another balloon. Very low pitched. This has been happening for about a week, and I haven't noticed any other issues (no loss of power, no high temp, no MPG drops).

Any idea what might be causing this?

I noticed that on mine not too long ago aswell. To me it sounds like part of the bpv, like when you do the bpv return line disconnect just without the wooshing sound. Strange though cause I don't always here it when boosting. Do you hear a similar thing?

 

[jeffknutson56]

It certainly seems to be related to the turbo- it's not high-pitched, more like a moan or groan from the engine bay.
How could I check if the previous owner did the BPV return line disconnect?

 

[That_grey_es]

U sure it's not when you let off the clutch pedal? And it's the clutch pedal making the noise?

 

[jeffknutson56]

U sure it's not when you let off the clutch pedal? And it's the clutch pedal making the noise?

Yeah, it seems like it's more related to the throttle, it'll happen when I'm cruising at 45mph and accelerate to, like, 60mph. It is less pronounced when I keep the throttle down- it's when I let up that the noise happens. Doesn't happen when I'm moving the clutch at any speed.

 

[That_grey_es]

Doesn't sound like a turbo issue to me. Sounds like a movement issue. I would double check tightness of motor and trans mount bolts. Especially the lower motor mount if you have the aftermarket one.

 

[R1600Turbo]

Bypass valve is probably sticking.

 

[jeffknutson56]

Bypass valve is probably sticking.

how can I check if this is sticking?

 

[PublicPotato]

Bypass valve is probably sticking.

Follow up question, any way to fix this besides getting a better bpv?

 

[PublicPotato]

Update:
I just installed the electronic boost control solenoid upgrade from n75 and it seems to have fixed the issue I was facing, although yours may have been a different issue I would still maybe consider it.