A few days ago I was driving and all of the sudden heard a strange noise coming from what sounds like the dash behind the radio or perhaps even the front end of car (but coming through the dash). It's hard to describe but it sounds like a steady, high pitched noise, almost like steam escaping a tea pot or something. It went on for about 20 seconds and then stopped. In the last few days, it's been more frequent.

I've tried various ways to isolate or recreate it but not having much luck. The sound doesn't change on acceleration or braking and it's not affected by turning heater fan on or off so don't think it's my vents. Today on a 45 minute ride, it happened about 6 times and each time stopped after 10 or 20 seconds. It is quite loud though.

I plan to take it to a mechanic and hope the sound will happen as he's driving it. But, in the meantime, and with what I realize is a vague description, any ideas what this could be?

Thanks

 

Check the level of engine coolant in the overflow tank. When it gets too low the radiator starts to suck air out of the tank which makes its way to the heater behind the dashboard. There it sounds like swishing noise or ball bearings rolling around.

If its very low, or empty, fill it to the HIGH mark with Genuine Honda Long Life Antifreeze/Coolant Type 2 from any Honda parts store. Its a 50/50 prediluted mix using deionized water.

Keep checking the level in the tank every day and refill as necessary.

I highly recommend not using another brand.

 

Thanks. The day after posting this the car started to shake at 60mph so I took it to mechanic. Put it up on lift and noticed that underside of car had huge chunks of ice in a few places (I'm in northeast) and it seems like those were the cause of noise and shaking. After a few hours in a warm garage, the ice melted and things seem back to normal. I'm hoping that was it!