Roman- I just notice the squealing sound actually continues even after the engine has stopped, like pressure is escaping, thoughts? You helped me earlier with a belt tensioner question...
hello, yes the engine light is on, the whining noise seems to be coming from the back of the engine. I listened to top of valve cover and turned engine off and whining stops slowly . This sound only happens when iding in or out of gear...
You may have a large vacuum leak.
This is why the engine light is on. A vacuum leak will cause the emissions to go up ultimately wasting fuel and causing a rough running engine.
You have a 2.0 turbo?
On top of the valve cover, under the plastic engine cover, there is a valve for the emissions system which internally leaks, in some cases it fails and causes the sound you are hearing.
Also make sure the oil filler cap is closed tight and the oil dipstick is secured in it's place.
Also called the "breather valve" or "oil separator"
If you’re getting puzzled by drivability problems take a close look at this pressure regulator valve or PCV. When these fail, the engine will lose boost pressure and also have trouble idling. It can also affect performance by not letting your engine receive all the boost air it is making. The part itself acts as a valve, providing a one way exit for gasses built up in the crank case, while retaining oil in the engine. When ruptured, it basically acts as a vacuum leak only less noticeable. If your car is showing some of these symptoms take a close look at this valve.