I hear a sound that sounds like water trickling through the heater pipes inside the car. If you slowly rev the car up from idle to 1000rpms or so, you can hear it. This is on a 1998 V70 T5. Is this a sign of something bad? I had the car in to the dealer for a coolant change, but the sound was there prior and after that visit.

On Toyotas, the heater hoses were the highest point in the system, and you couldn't get all the air out. I heard this noise in my Supra. On this car, the heater hoses are nice and low, so I'm confused

 

Could be the evaporator. Hope it's not. Mine went bad in my 02 S60 and it was a $1300 repair. Is your cooling working properly? That was the first sign that mine was going bad.

 

By cooling you mean a/c? Yes it works. Recent new condenser last year.

 

It looks I got the similar noise came from driver side dashboard. Does your noise come the same location?

Daniel
2009 xc90 3.2

 

Yes. Sometimes, I'll kneel outside the car, put my ear down by the brake pedal and press the gas pedal with my RH to hear it better.