Q: I have a 2005 Chevy Tahoe that did not give any strange sound until a year ago when I heard a “whining” sound under the hood. I took the Tahoe to the dealership and complained about the annoying sound. They purported they did not hear the sound I was talking about. So I let it go since it did not affect the performance of the engine. At times the whining sound will abate somewhat and then again it will be noticeably profound. Your expert opinion is much appreciated as to the cause of this sound and will it affect the engine’s performance in the long run? Thank you very much.
A: Noises are the hardest– especially if they are intermittent. It’s very difficult to speculate what it is or whether you should drive or not until the noise is heard and diagnosed. Alternators make noise when over-charging, transmissions along with belt pulleys make noise… basically anything that spins can make a noise that might not sound normal. My suggestion would be (if you can) to drop the vehicle off with the shop of your choice for a day or two and let them drive it off and on. We have in the past (with customer permission) had one of our technicians drive a vehicle to and from work trying to duplicate problems. If you can hear it, then there is an issue that needs resolved—taking some extra time with the vehicle might help solve the problem. A good repair shop will understand this and take the time to help you resolve the issue.
We had a technician at one of our own shops that had a very similar experience. His 2001 Chevy Suburban had a very comparable intermittent whining noise coming from under the hood while driving down the road. The sound was like a whistling noise and would only be audible for a few seconds in the beginning and then eventually started to get louder and last longer as more mileage was put on the vehicle. It ended up being the serpentine belt tensioner that fixed the problem. This might put you in the right direction to point out to a qualified technician—but please keep in mind it could also be a number of other issues. Some shops, like ours, do provide free vehicle inspections. One of our ASE Master technicians will drive the vehicle with you to help identify the noise you are concerned about and then visually inspect to locate origin of noise.