My Civic just started making a noise I can only describe as a whine. It sounds mostly like the noise you get from reverse gear, but louder and mostly higher pitch. As the engine spins up from idle, the noise becomes pretty loud and the pitch varies exactly with engine RPM. Once the engine really warms up—not just coolant at full temp, but several minutes after that—I can’t hear the noise anymore. Any ideas?
I noticed this for the first time the day after getting an oil change, after the car sat overnight and fully cooled down. I have checked the dipstick and it appears to have the right amount of oil. (It’s surprisingly hard to tell when the oil is new and clean!) I’m pretty sure they put in the right oil weight. In any case, all the oils they had “on tap” were 5W-something so should behave the same when the engine is cold. The day I noticed this was also basically the first day the temperatures here dropped about 20 degrees, but that just don’t seem like it should matter. It doesn’t take long for the engine to warm up 20 degrees, but it has to get a lot hotter than that for the noise to go away.