I just completed another 3500km journey over 5 days. The outside temperature varied between 38 °C and 46 °C during the day. This meant I was using the aircon the whole time. During this time I was lamenting the leather seats as it was causing a lot of heat and sweating.
This caused me to focus on the aircon while driving. While driving in ECO mode and the fan speed fairly low I can hear a undulating whistling sound. This undulating whistling sound was replaced by a more consistent and quieter whistling sound when I switched back to normal mode. The undulating sound also went away completely when I switched off the aircon, so I am confident it is the aircon causing the noise. Anyway, the rest of the trip was done in normal mode as I needed full aircon functionality.
I have not heard such noises in my previous cars, but have heard it before in office aircons that seem to be operating inefficiently, perhaps on low gas levels. Maybe it is a sign that the gas was never filled properly at manufacture.
The aircon performance has been consistently mediocre from the start. Even at these high temperatures it would still blow out cool air, but not really cold enough to cool down the interior to such an extent where the passengers feel comfortable.
What is interesting is that the undulating sound is in ECO mode, and this may be the way that Volvo is reducing the aircon load on the engine to save fuel.
Thank you for reading my very long and convoluted story. My questions are:
Do you also hear this undulating sound caused by your aircon when in ECO mode?
Is this normal or a defect?
Does your aircon cope with the heat?
I guess I wont be getting any responses from Europe as its probably too cold to switch on the aircon at the moment.
Cheers and all the best for 2017