Honda Fit sloshing noise that sounds like it's coming from dashboard

I took my 2007 Honda Fit Sport for the 30,000 mile service on 12/1/07 at Hollar Honda in Orlando, Florida. After waiting about 3 hours and paying $300 I left the dealer. As soon as I left I heard a sloshing noise. It was like fluid going back and forward. I found it kind of odd that it never did it before the 30,000 mile service. I called the dealer and they said if it didn’t stop doing it to bring it back. Well I brought it back after a week. They didn’t know exactly what it was but they claimed they flush the air system or something and that took care of it. I didn’t get any paperwork but I didn’t think anything of it. After about a month the sloshing noise came back and I took it back the morning of 12/19/08. I had to talk to the service manager because they didn’t have any records of this ever happening in the first place and I had them added to my records. They were not able to find a problem and they claimed they found the following “Honda service news article” that says: “The Fit’s fuel tank is mounted under the driver’s and front passenger’s seats. Because it’s located there, it can make a sloshing noise that sounds like it’s coming from the dashboard. That noise is just a normal characteristic of the vehicle and nothing you can fix”. I’m assuming this article is real but I can’t find it anywhere on line. Any suggestions for me? Help!

Have you heard the same sloshing sound when the tank is full? Does the noise increase as the fuel is used?

Other similar noises can be heard from the heater core when there is air in the cooling system and when the A/C or fresh air vent drains are plugged.

If it IS in fact the result of the fuel tank making the noise, I feel for you. No amount of insulation is going to mask that noise. Sounds like a poor design to me.

If they changed the coolant, I also would suspect air in the cooling system. Not sure how to bleed it out, though…

Most times air trapped in the cooling system will ‘burp’ the air out via the cooling down period after the engine is shut down. The air is released through the coolant reservoir.

If not, before starting a cold engine, remove the rad cap (or the pressurized coolant reservoir cap,if so equipped) and idle the engine and watch for air bubbles. When they stop, seal the cap tight.

Some engines have a (coolant) air bleeder plug/valve/screw close to the t-stat. You have to know your engine to find it.

Check the scheduled maintenance on your Fit. With the warranty its hard to find $300 worth of owner required maintenance at 30,000 miles. I believe the first major items occur at 3 years or 100,000 miles.

We hear sloshing of fuel in our Fit, it’s no big deal. That’s what happens when the tank is under the passenger compartment of a car.