12' WRX. Boost Leak? Turbo Bearings? #7 Bolt? HELP!!
I have a bone stock 2012 WRX. 12k miles. No issues to date. The problem i'm experiencing is a whistling sound when my turbo kicks up around 3500 to 4000 RPM. Its a pretty noticeable sound. 2 thoughts come to mind. Leaking air (boost leak) or bad turbo bearing? My oil level is perfect and i've changed it ever 4k.
Here is the interesting part that might be a MAJOR clue. When I changed the oil at 4k, there was a bolt sitting in my plastic under guard. It is a bolt with a #7 on it. Similar to those which I can see on intake parts and other plastic parts under the hood. I am guessing the 7 refers to a torque spec? Is there a complete listing of where #7 bolts appear? It looks to be a 30mm long M8.
What im hoping happened is that the bolt being out finally cause the high pressure air to leak thru.... but I was hoping someone has information on the locations of these bolts so it can be the first attempt at resolving the issue.