Knock Knock Knock....

[scooby-x]

I am having a weird knocking sound when I let off the gas and it goes back to idle. I thought it might be rocker knock, but when I took it to the dealer the service manager and I both noticed that it is coming from behind the engine... could be the turbo or something. Now could this be the wastegate, or is it a busted fin, or worse off is there mad shaft play in the turbine? And might this be fixable? Thanks

Oh and it will do it at idle after a spirited run....


Basically I am wondering if anyone else has had this sound pop up on them. It sounds just like a rocker knocking....

[scooby-x]

come on someone has to know...

[Darrell]

Someone on here probably does know, but they may not have been on between 5 and 6:30 tonight. Patience.

[scooby-x]

bump the question...

[pghWRX]

I have the same problem. What was the cause/fix. Thanks.

[Station]

I also have noticed this knock at idle on my 05 WRX.
I dont notice pings or knocks while accelerating thru any gear, just while at idle.
It happens when I start the car cold and when its warm after my 30+ mile daily commute.

Any thoughts?


EDIT- Oops, found the answer elsewhere, Search button is my friend. Apperently this is a known issue and has been answered in other posts.

[CAPETANN8]

if its cold and you start up boxer engines are very loud, knock and make noises, just let it warm up.......
HOWEVER
if you drive the car around and the car is at OPERATING temperature, and your at idle and it still sounds a little knocky, i personally noticed if the engine is not completely full with oil (4.8 quarts) (i normally put in 5).....it will knock even at just a half a quart low the engine is loud.......i notice about every 1500 miles i will be a little oil maybe half quart sometimes more, especially when i use a thinner oil 5w 30 mobil 1, in the summer i put 15w 50 mobil 1, doesnt burn at all.......check your oil, if its more than that, i dont know what the problem, but boxer engines crave perfect oil level

[gda03subaru]

i have this same noise coming from the top of the block on the back side of the motor. at first i though it was bad gas, so i drove it completely out and went to a different station and got premium, still there. so i changed the plugs, still there. If the car is at idle and you tap the gas a couple of times it goes clack or knock then goes away does fine with no noise under acceleration but as soon as you let of the gas you hear it again breifly just started a couple of days ago very disturbing sound anyone know