Hey Scotty and the community, I hope you all had a great start in 2025! I live in Europe and have a 2004 Volkswagen Golf with 150k miles. 2.0 FSI engine, standard transmission (6-speed). When I drive on the highway, I sometimes notice a whistling sound, which gets higher (pitched) the higher the RPM. It used to be very quiet, but now it can be pretty loud, not extremely, but you can hear it well. It only happens sometimes though, it doesn't whistle everytime I drive, for instance yesterday I didn't hear anything at all, at a driving distance of 976 km (610 miles). When it does whistle, if I go 50 mph or 140 mph doesn't make a difference (except for the higher wistling the higher the RPM). No engine codes or anything. What could it be?
Well of course you have to pinpoint where the sound is coming from. See my video finding the source of car noises. Often it is air whistling through a gap somewhere in the car windshield, fenders, whatever
@scottykilmer Thanks for the response and the video! Well, it definitely is coming from the engine, because as I mentioned, the whistling changes in its pitch frequency (not sure if this is the right term) as the RPM change. What I mean is, let's say I travel in 5th gear at 75 mph at about 3.3k RPM and shift into 6th gear. The RPM drop at 2.9k RPM and so does the whistling sound become lower pitched, even though the speed is still at 75 mph. Perhaps some plastic thing or something is stuck inside the engine, I'll have to check it out. Thanks a lot!