On the way home when I got off the highway I noticed a high pitch whining like a whipple supercharger comming from my engine. I first thought it was the bearings in my alternator where going, or my water pump. When I got home I opened the hood and had a listen. It is coming from what I can tell the middle at the back near the top of the engine. When at low rpm it sounds a bit rattly but when reved it, it sounds like a whine. Cam bearings? Piston pin? It doesn't go away at any RPM gets high pitch the higher I rev. Any thoughts.

The engine has 380k km on it. Timing chain and stuff is newer (20 000k ago). Engine runs fine. It has been very cold -25C in the mornings so I am thinking the cam bearings were running in molasses for the first few minutes.

 

It's from being so cold. My gf's Saturn has been doing the same thing the last couple days here where it's been -10F with a high of 0F during the day.

Rob