RockSalt wrote:I have the same issue reported by tobiassej, and just scheduled an appt for next week. When driving over 30mph with the heating on, after several minutes a loud buzzing noise like a rattling bathroom fan starts. Each time the vehicle slows below 30mph to stop, the noise subsides. when the vehicle speeds back up, the noise returns. If while driving with the heat on and the noise present, I shut off the heating, the noise goes away. If I then turn the heat back on, after a minute or less the noise returns. Based on other reading I suspect this is the compressor for the coolant system that cools the batteries, which would presumably be under load when driving over 30mph with the heat on. However it does not make sense that the system would run continuously as it does when driving with the heat on or be that noisy.
Update: The shop had the car for 2 days, and did several test drives. Both a technician and a shop manager verified the noise and confirmed my suspicion that it was coming from the coolant system compressor. They opened the car and found that the compressor was literally disintegrating, the process spewing metal fragments into the cooling lines. So now I get to wait 2 weeks for parts from Germany, and the dealership needs to not only replace the compressor, but they need to flush all of the cooling lines, including the lines that run through the battery pack, which they need to remove from the vehicle to do. Wow. All from an annoying noise! Also, anecdotally, I have noticed my post full charge mileage prediction decreasing, and when driving the predicted available mileage decreases faster than I am able to drive, i.e. 25 mile range prediction nearly leaves me stranded after 16 miles...I hope that what appears to be a failing cooling compressor is what was also contributing to reduced mileage, as the battery was not being properly cooled? Hopefully once the compressor is fixed, I get my range back too.