I noticed this on my car from about three months ago, and was wondering if anyone else had the same happen at 75mph. When cruising steady at 74-77 mph, the engine makes a high pitched noise (audible but not loud). It only happens at these speeds. Past and below that mark, it's quiet and smooth. Any ideas?
Something I noticed at 75mph...
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Could be the differential whine that's plaguing a lot of people. Does it just happen recently? Or is it under light throttle?
A couple of things too, it can be tire noise (the fact that it only happens at certain vehicle speed, not engine speed triggered this suspicion), or it can be the famous "cold air intake" whine.
Try this: Rotate your tires and see if that elimiates the noise. If so, then it's tire wear. If not, it may be the differential wear. Try a new air filter as well, and if that alleviates (but not completely eliminate) the noise then it's the valve behind the mass air sensor that's causing it when air is rushing through the valve.
Otherwise it's the differential whine. Search here and .org for the TSB number and bring it to your dealer's attention.
A couple of things too, it can be tire noise (the fact that it only happens at certain vehicle speed, not engine speed triggered this suspicion), or it can be the famous "cold air intake" whine.
Try this: Rotate your tires and see if that elimiates the noise. If so, then it's tire wear. If not, it may be the differential wear. Try a new air filter as well, and if that alleviates (but not completely eliminate) the noise then it's the valve behind the mass air sensor that's causing it when air is rushing through the valve.
Otherwise it's the differential whine. Search here and .org for the TSB number and bring it to your dealer's attention.
Things react to certain frequencies.. perhaps that's all that is going on.. at 75mph your X" wheels are turning at Y RPM, etc etc.
My old car would vibrate at particular speeds (between 48 and 50mph, and between 92 and 95mph).. shortly before it was totalled I had replaced my wheels, which did change the vibration marks (the vibration between 92 and 95 disappeared, may have moved up too high for me to find)
My old car would vibrate at particular speeds (between 48 and 50mph, and between 92 and 95mph).. shortly before it was totalled I had replaced my wheels, which did change the vibration marks (the vibration between 92 and 95 disappeared, may have moved up too high for me to find)
Definitely not tire noise, and I don't have a CAI. It's in light throttle (can't be heard during acceleration, but when coasting at those speeds). I'll take a look at the differential whine, but I'm still wondering why it occurs only at those speeds.The HACK said:
My dealer said it was the VANOS air intake. Could be the diff...I had the "butyl tape fix" applied to my car by the dealership, and it's still there. Gets especially pronounced in bad weather and/or when the engine is under heavier load (ie, passengers, hills, etc), which leads me to believe it's engine related.
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