Q: Sloshing noise on startup

asked by on June 09, 2016

I hear a sloshing liquid sound coming from the air during car startup. Any ideas?

The first thing to do is check your coolant and see if you’re low on fluid. When you are low on coolant, air bubbles are created and these air bubbles will slosh through the dash because the heater core is located there.

In today’s modern vehicles, it doesn’t matter if you have the heater turned on or not, the water is constantly circulating through the heater core. The only thing that keeps you from getting heat inside of the cabin is that the blend door to the heater box is closed. When you turn the heater on, it opens that blend door and the hot air goes through the heater box, allowing the air to come out hot.

That being said, your problem could be simply low coolant levels. Also, have your refrigerant for the AC checked as well because if it’s low on refrigerant, it can make a sloshing sound too.

If you need help with these checks, contact a certified mechanic who can ensure your coolant is topped off and diagnose the sound firsthand.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Grinding noise from tire

If the noise is constant, it may be the bearings. If the noise is only when braking, the noise may be brake related. Bearings typically make roaring/howling noises, while brakes typically make squeaking/grinding noises. A test drive and visual inspection...

Car moves in 1st gear and reverse but won't move in drive

Hello, first thing to check of course is fluid level. If the fluid level is low, any number of weird symptoms can occur. Your symptoms sound like the valve body may be sticking from a bit of grit or leaking...

Only getting luke warm heat out my vents

Hello. The heater is a part of the vehicle's cooling system and uses the same fluid. The first thing I would do is check to make sure that the system is properly filled and bled. If any air gets trapped...

Car cannot start, check engine light on

A vehicle that cranks but doesn't start indicates a problem with fuel delivery, ignition, or compression. A vehicle that doesn't crank at all indicates a problem with the starting/charging system or an internal engine mechanical problem. You said the Check...

No heat after adding coolant and thermostat almost to H

Hello. If the coolant was that low then that will cause the heater to not work. The most important thing at this time would be to determine where the coolant went. For it to be this low that means it...

Bad experience with CVT

Lemon laws vary by state, but in general, the manufacturer has three attempts to successfully repair the original concern before Lemon proceedings can begin. In regards to notes that should be made when replacing the transmission, be sure that the...

Vehicle shuts off intermittently at idle

The P0113 code relates to a problem with the intake air temperature (IAT) sensor. The computer is seeing a reading that is outside of its normal parameters and is causing the computer to set the code. This could also be...

Car makes noise when taking off fast

You may need to have the engine mounts inspected to see if one is broken. This would be why you hear it in drive and not reverse; the engine may be moving and causing the noise. Have the noise...

Whining noise coming from car

Hi, Nissan has released a TSB (Technical Service Bulletin) regarding the issue, NTB09-128. You can search it if you would like detailed information on what the repair is. The sound is coming from the timing chain rubbing against the guides...

Related articles

What Sensors in the AC Tell the Car If the System Is Working or Not?
The The average car today contains a bewildering range of sensors that feed information to various computers to monitor everything from air intake to emissions and engine timing. Your car’s air conditioning system also contains a couple of sensors that...
How to Recharge Your Car Air Conditioning
Car AC refrigerant has to be recharged occasionally. Add more refrigerant to your AC system to keep your car cool in hot weather.
How to Buy a Good Quality Heater
In In the dead of winter, when the cold air is nipping at your heels, nothing is better than climbing into a nice, toasty warm car. However, having a heater problem like a heater that blows cold air or leaks...