My wife's 98 V70 AWD has recently (last 3-4 months it has become progressively louder) developed a noise at idle, which stops when the car is being driven. Initially, this was just while the car was in "park" and would subside when put in gear. However, over time, it has become louder and in addition to disappearing when driven, it changed pitch while shifting from park into gear.
What might be the cause? Is this something that can be easily fixed at home?
Thank you, Dave