2005 with 110K. Last winter had some really cold weather in New Hampshire, lots of mornings below zero. Started to notice top end engine whine and started replacing components, Idler wheel pulleys, alternator. No change. Once warmer weather (spring) arrived noise went away. Starting to get some cold mornings again and noise coming back. Get this even after truck warms up. Only at RPMs a bit above idle though about 1500 RPMs and then you don't hear it any more while driving until you stop and accelerate again. Using factory recommended 10-30W oil. Any ideas? Thanks!!